FSX (and P3D v1.x) Software and Hardware Guide

Hello everyone.

This guide has two sections: the Software Guide and the Hardware Guide. Please scroll down for the Hardware Guide. It has been on purpose left in one piece.


Version updated 25. March 2014.

*P3D – has not been extensively tested, but has been confirmed that some tweaks work, and most of the document can be applied over P3D (ONLY APPLICABLE to version 1.x, NOT v2.x). “*” after each tweak explain what it does/doesn’t do for P3D.

I’ve been a member at many forums in past 10 years, helping users in their FSX setups and the questions that pop up are usually often very similar. This guide was created to answer those questions and in general to help users set up FSX. It also serves as a reminder and the one stop place for all those tweaks you wanted to know about.

Many wonder why I have no problems with performance, so I also wanted to share my settings and also explained a bit why I set it like I set it.

And before you ask: no, I am not getting 30fps in every situation, I also fly heavies, and I have sometimes FPS below 30s and I then do have stutters occasionally.

IMPORTANT: If you feel like going through this guide and set up my tweaks, I strongly suggest you start doing that on the clean FSX, meaning clean fsx.cfg, no mods like ShaderMod 3, no other tweaks, especially not tweaked FSX.cfg through Venetubo tool (not saying Venetubo is bad, only that this is a different approach).

The numbers you are seeing in each of the tweaks are my own settings.

FPS measurement references in this guide are done with FRAPS, not with an internal Shift+Z counter.

Let me also point out that these tweaks are most probably going to work best on the Sandy Bridge/Ivy Bridge system, coupled with an Nvidia GPU. I have no idea how well they will do on the lower systems (or ATI cards), but you are welcome to try and report!


FFTF – Fiber Frame Time Fraction
SGSS – Sparse Grid SuperSampling
AA – Antialiasing
AF – Anisotropic Filtering
IQ – Antialiasing and Anisotropic Filtering, IQ is basically everything that falls under this category, whatever is making the picture look better (smoother edges, jaggies and shimmering elimination etc.)
HT – Hyper Threading
TBM – Texture Bandwidth Multiplier
TML – Texture Max Load
BP – Bufferpools
SB – Sandy Bridge
AM – Affinity Mask
OOM – Out of Memory


1.x has no reflections:

- Low 1.x – the basic shader
– Mid 1.x – adds an animated detail texture
– High 1.x – adds some specular effects

2.x adds a 2nd pass to get reflections and this can be a killer:

- Low 2.x – only the sky (including sun, moon and stars) and aircraft are reflected
– Mid 2.x – sky, aircraft and clouds are reflected
– High 2.x – sky, aircraft, clouds and terrain are reflected
– Max 2.x – sky, aircraft, clouds, terrain, autogen and other scenery objects are reflected

Let’s get going:


If following entries don’t exist in your FSX.cfg, enter them manually!

/ Usepools=0 (use either or, both do the same thing) – referenced as BP=0

This tweak bypasses the internal FSX bufferpool, and sends the data directly from the CPU to the GPU. Benefit: higher frames, Downside: possible artifacts. A very good balance with locked FPS is required!

Water Effects must be High 2.x or higher, otherwise you will get flashes.
Often seen in combination with other tweaks, especially with RejectThreshold:
In the Bufferpools section, if BP=0 is used, nothing else is required or should be in there.

If you get flashing and artifacts with BP=0 tweak, it would be a good idea to check what the GPU is doing – running a GPU at 100% is a source of artifacts, flashes, driver crashes and BSODs. As the CPU sends the data directly to the GPU, and GPU is not able to handle the incoming data, you will get flashing and artifacts, as already mentioned. The only way is to lower the settings, cloud resolutions, or anything basically that is going to give the GPU more headroom, including buying a faster GPU.

*this tweak can/should be used in P3D (I am using it). The benefits are very similar to those in FSX. Also since High 2.x doesn’t exist in P3D, the setting should be set accordingly to FSX. See the water reference section above.


This tweak, on a quad core, moves the FSX onto the Core1 (2nd core), to basically split fibers and main thread. It is good because Windows is usually having its processes on the Core0, so moving to Core1 is giving FSX more breathing space. It is also sacrificing one texture thread, since all that comes after Main Thread are Texture Threads. This means FSX is running with Core0 – Fibers, Core1 – Main Thread, Core2+3 – Texture Threads. That’s OK like that.

For a quad core running HT off, this should be 14.
For a quad core running HT on, this should be 84.

How to calculate AM:
A modern day SB CPU has Cores. Depending if you HT is on or off, you are going to have 4 or 8 cores or even 6 or 12 cores on the 6core CPU.
Now, a quadcore has: Core0 (being the first core), Core1, Core2 and Core3. Cores always begin with 0.
AM is being calculated easily in the windows calculator. Open and then choose programmer view. The binary code is shown below, and it corresponds to cores on the CPU. But you have to calculate backwards. This means, lower row, far to the right, the numbers represent cores. See this pic:

An example:
For a quad core running HT off, this should be 14. Type in 14 into the calc. Observe the numbers in the binary change. Now remember: they are backwards.
So it displays: …. 0000 1110, meaning cores 1,2,3 are used.
Same for 84 (if HT on):
…. 0000 0101 0100 meaning Core 1,2,3, and no HT cores are used, also Core0 is not used.
If you wish, you can test whatever you like here, just change the 0 to 1 or vice versa with the mouse to assign active core to FSX.

*this tweak can be used in P3D the same way as in FSX


A must have tweak. Don’t ask much :) (Thank you Jesus!)

*this tweak is not needed in P3D


I haven’t seen any benefit of going any higher. There are some posts saying you should set it to 80, 90, 100… I keep it at 40, which is also a default.

Another possibility here is to calculate this number according to some posts.
These formulas have been assembled by FSX users and in no way confirmed by Microsoft, so use at your own risk. As it is with all tweaks, it’s worth a try.
FSX Tweaks Demystified


(GPU Memory Bandwidth * 24) / Target Frame Rate = Maximum Bytes per Frame
24 is used for GDDR5.

(Maximum Bytes per Frame / Global Texture Resolution) * 100 = Texture Bandwidth Multiplier

The important thing here is to think about the Global Texture Resolution: do you have 1024, 2048 or 4096 in your CFG, so what are you going to put as a divider? Taking 4096 is going to give below 40 result. Also do you set 4096 when you have no 4096 clouds installed, or not… NGX has 4096 textures etc. I went with 40, and personally saw no real benefit from calculating this. As always, YMMV.

*this tweak is not needed in P3D


This is a tweak telling FSX what is the max resolution texture it can load. Remember: can. If you are running absolutely no 4096 textures, there is no reason to have it set to 4096, but also no harm done.

It is no performance killer if you are not using 4096 textures. Examples are LevelD McPhat HD textures, 4096 clouds…

Beware that using 4096 clouds with high levels of Anti Aliasing like SGSS is going to kill the GPUs, especially 560Ti. Even my overclocked GTX 580 is being extremely hammered by such high resolutions and IQ. I am currently using 2048 clouds, as they offer a good inbetween. Depending on the GPU, you might be better off by 1024 or 2048. If DXT5 or not, I don’t know. Saw really no performance difference and no difference in VRAM usage. I opted out for no DXT5 and got into no troubles.

This value is likely to get reset if you enter and confirm FSX settings in-game.

*P3D supports 4096 textures natively via options


Many are using external limiters, many are using internal.

I found out (and got it recently confirmed) that external limiters cause blurries and more stutters.

The fact is that internal limiter is as smooth as FSX can get, if FSX achieves the limited FPS without a problem. If you combine this with the BP=0 tweak, you are going to get even better smoothness.

30 is not a magic bullet for everyone, although it’s probably the most used setting. Doesn’t mean it’s going to work for everyone though. If you have older hardware, you might be forced to go lower, 20-25 even. It’s all about what your machine can handle, considering both hardware and settings. The best though would be to aim for 30fps, due to the new VSYNC tweak.

Setting higher FPS is a bad idea and should not be done, much same like running unlimited.

*this should be set the same in P3D


A thing worth mentioning here is a new discovery on the Hardware Video Forums about new Nvidia VSync.
This tweak brings unparalleled smoothness with the locked frame rate at 30fps.

In short:
1) identify your monitor refresh, and if it’s 60hz…
2) set locked 30fps in FSX FPS and see that you get it!
3) set Nvidia Inspector like mine when it comes to VSync – ½ refresh rate

This tweak only works in full screen. It does not work in windowed.

ForceFullScreenVSync=1 in FSX.cfg is not used in my configuration.

Source for more details:

*same as in P3D


If you are a windowed mode user (multiple screens for example), then you will be please to know there is a “fix” for Vsync in the windowed mode.
Previously, when Vsync in windowed mode was activated in FSX.cfg per ForceWindowedVSync=1 line, the FPS would always run at refresh rate dividers… 60, 30, 15… meaning, it was never able to run 25fps, or 23… from 30, if system could not maintain, FPS would drop to 15. And that led to quite a lot of stuttering. There is a fix now: after FSX has been started, an Aero restart is required, which in return fixes the normal Vsync operation in windowed mode.

To enable Vsync in windowed mode add following to your FSX.cfg:


To restart Aero, there are more possibilities, choose yours:

1) manually – quit dwm.exe (task manager, Desktop Windows Manager), it will restart itself, and Aero will be enabled

2) create a batch file containing:

@echo off
start “” “E:\FSX\FSX.exe” (insert here the link to your FSX.exe)
net stop uxsms
net start uxsms
and run it. FSX is going to start, Aero is going to get started after FSX, and voila…

3) elegant solution, through FSUIPC (only works with registered version):

a) create a batch file containing:

net stop uxsms
net start uxsms

b) set the FSUIPC to run the batch file automatically, edit the FSUIPC.ini and enter:

Run1=HIDE,”E:\FSX\Modules\FSX.bat” (insert here the link to your FSX.bat)

This solution is going to do everything silently. No CMD popup windows, only visible Aero activation.

Reference post:

*can be used the same way in P3D, not needed though


This tweak is for sharper distant textures and basically extends the sharp texture radius around the aircraft. It takes a toll on performance and especially memory load (VAS).

This setting should NOT be set over 6.5. This is a known source of OOM errors, and even 6.5 can cause it, if you are not careful. Max FSX default is 4.5. And it is going to reset to 4.5 each time you enter AND confirm the settings screen in FSX.

And important tweak that goes along with higher LOD is the ZOOM. More you zoom out, sharper the textures are going to get! I am using default of 0.6 zoom in all my views.

*P3D has this setting by default in the options, but be aware that VAS usage is in P3D slightly higher, thus higher chance of OOM with LOD 6.5

OOMs (Out of Memory errors) and why they happen:

To keep this explanation simple: FSX is a 32bit application thus has an ability to grow up to 4GB of virtual space. This has nothing to do with the free space on the disk, installed physical RAM or the size of the RAM. VAS (virtual address space) is a memory map in which FSX is working. If FSX attempts to grow above 4GB of VAS, it will crash. VAS is mostly impacted by the LOD setting, additionally through heavy aircraft like PMDG NGX and ORBX sceneries like PNW or similar. UTX also puts a heavy usage onto VAS.

VAS can be easily monitored by either FSUIPC (a warning when VAS reaches about 3.8GB, giving your a chance to save the flight) or visually through Process Explorer (a column Virtual Size must be shown!).


This should be used if you have a widescreen monitor, which I think everyone has nowadays.


FFTF determines the fraction of the CPU time given to the scenery loader in relation to the time spent rendering. Basically it’s a relation between the scenery loader and faster FPS. Run it lower, you get more FPS. Run it 0, you give CPU no time to load scenery, if your FPS is below locked. The faster the CPU, the lower this number can be, because less fraction of the CPU clock is required to successfully load the scenery.

This tweak is also dependable, much like the BP=0 on the balance of the system. Meaning overloading the system and hoping that FFTF=0.1 or lower is going help you bring the FPS up is a misconception. It’s very hard to explain what an overload means, but if you look at my cloudtest, that is a clear example of an overload (even my Windows seem laggier if I run that in windowed), even though the FPS I get are around 26fps.

So in short:
Default is 0.33. The lower the number, the better the FPS, but also more danger of blurry textures and autogen loss.
DO NOT set it to 0.
You can experiment with this tweak; mostly used settings are 0.1-0.25.

ORBX lands are usually going to need 0.2 or higher, anything less and texture loading will greatly suffer. Outside ORBX you are probably be able to run as low as 0.1. Experimenting is the key here.

*can be used in P3D, shows the same results in P3D just like in FSX (higher FPS, and if the setting is too low, blurries)


It has been for some time known that in FSX, the mouse cursor can cause certain FPS drop. It has always existed in FSX, however became known with the appearance of high quality cockpits that were hard on FPS. For example PMDG 737 NGX. If you are locking the FPS like I suggest in this blog, then your FPS are locked 30fps. Now, it will still happen at detailed airport hubs that your FPS drop below 30fps in the NGX VC. Say your FPS drop to 25. And the issue of the mouse-cursor lag or fps loss is simple: is there visible mouse-cursor over the FSX screen, the FPS will be lower than they are when the mouse is hidden. The mouse-cursor hides automatically after some 5 seconds if you do not move it. However, one might wish to hide it, not waiting these 5 seconds.

Beware, this is not really a tweak, it is only a way to help yourself gain couple of FPS during worst of times like taxiing on a big airport or on approach where FPS suffer due to high quality scenery.

Also note, that this “tweak” does not help if you are GPU limited. For example low speed GPUs, or extremely high levels of Antialiasing, which would put your GPU usage to 100% and limit the FPS on the GPU.

So, how to:

In windowed mode, it is pretty obvious, just move the mouse cursor off the FSX, and you will most likely notice FPS go slightly up (usually about 20%) – as long as your FPS are BELOW what you have locked, otherwise they can’t go up, obviously!!
Full screen is a bit more tricky, so I use two tricks – in NGX, there is a possibility to move to the left upper edge of screen, that is basically the same, or I personally use EZCA – I have a mouse button assignment for cockpit pan of EZCA, which then conveniently hides the mouse cursor and switches the mouse to react as a pan-around. Also if switch to another screen, like I do via InputDirector does the trick. There are many tricks, the main thing is, cursor is not visible over the main FSX screen.


[DISPLAY.Device.NVIDIA GeForce GTX 580.0]

The line DISPLAY should appear ONLY ONCE per Display in your FSX.cfg (if you have one display, once, if you have two, twice etc).
If you have more lines (and only one monitor), delete fsx.cfg and let FSX recreate a new one.
The “Mode=” end number should be 32 (NOT 16).
Anisotropic Filtering should be on in FSX.

Now, what does this combo of tweaks do FOR ME?
First of all, I tested which settings in FSX do the most damage to the FPS, and I removed those.
Rest I put almost to the max. I’ll just post my settings here, and let you do the math.


I am not using any AI since I exclusively fly on VATSIM.

I combined BP=0 tweak with the FFTF successfully, giving me the best ratio in performance vs. quality (means no blurries) and least stutters.


So, after going through my tweaks, I would like to come back to something I have to explain again and again:

People are reporting very often that some tweaks are not working, especially that BP=0 is stuttering, that you get artifacting. While systems might differ, and they most certainly often will do, I had one sole experience on most of my systems.

If I manage to balance my system well, I will get no problems from any of the above tweaks.

What does this mean:

It means that before you even put the single tweak into the FSX, you make sure it runs well in the basic setup. Important to understand is that first comes the good balanced setup and then comes the tweaking. I’m not saying you must get 30fps in the NGX VC in the KJFK, but you should see that your settings reflect your system, turning off those FPS killers like bloom, cars, extreme autogen etc. As you noticed, I run all scenery details on max, except autogen and clouds. I did simple tests to see what diminishes performance in FSX at most, and I removed that. As I posted on one thread, if you put enough FPS killers together, it’s gonna kill your FSX, but it also applies the other way. Also do think about those beautifully looking 4096 clouds. Using 2048 or 1024 are not as bad, and won’t hammer the system as hard. This is GPU dependant.


There is one uncharted tweak in the FSX community. A skidmark tweak.
If you do a simple test, you can easily confirm it:
Set FPS unlimited for this test. Go to a default good performing airport.
Take a default aircraft, slew in for landing and land. Change to external and look behind aircraft. Note the FPS.
Now rename/delete fx_skidmark.fx in Effects folder. There is no visual difference for me, maybe someone can show me visual difference here, but more important for me:
Repeat the above test and note the FPS when looking behind aircraft. My FPS was way higher.
I tested this on completely default untweaked FSX and had it confirmed.
There is something with this file that makes the FPS drop a lot after you land and you turn to spot view. It was even more obvious when landing in the heavy airport, where FPS really mattered.


One thing that I use quite often is a configuration save/load feature in Graphical Settings.
Say you change something in the settings, if you have custom LOD and TML, you are probably gonna see a reload with LOD 4.5 and TML 1024.
As this can be impractical in flight, there is a way to reset those settings:
Save settings to a file. Open the file in notepad to edit it, set your LOD and TML data back to your settings, save the file and then load it in FSX. FSX is going to load these settings, along with your newly set settings. This can be done with one file only one time. You can’t save/load one file two times in a row. That is why I have two such config files, you can alternate them while FSX is being open.


Pete Dawson, a maker of FSUIPC utility for FSX, has implemented a g3d.dll crash fix into his product. The fix that is implemented covers one of the crashes only – it is NOT all miracle g3d.dll crash fix.
You should install (and actually buy) the latest module from his website.



There is a know bug in originally installed FSX, when you click into menus a lot, or click around the cockpit, or right click, that FSX is going to freeze and/or crash.
The problem is known to get fixed by saving a Vista UIAutomationcore.dll file into FSX folder. Just by placing it there, FSX seems to use that file and not crash FSX any more by those clicks.
Link to the file

FPS Limiter: Internal or External?

Now, I read all those posts claiming how the external limiter is great, and way better than internal FSX limiter. I changed 3 computers since I had FSX; I tested external limiters on all 3 computers and found that all 3 behaved in the completely same manner – way worse than an internal limiter. Thus it’s very hard to believe there are computers out there that behave differently. My only explanation is that the internal limiter wasn’t set up correctly. I feel bashing coming now, but that’s how it is.

To test the limiters, situations must be set up to reflect the test you are trying to make.
An example: how to test a stutter? Do you go flying around and judge by the feeling? Do you count how many times it stuttered? Did you turn slower or faster? Did you also pull on the stick?
There are too many factors here, and most users do that. I don’t blame them.

One of the correct test situations, which I figured were the best for me for stutter testing are like this:
I have a saved flight with a 737 on the runway at KSEA, setup with parking brake on, and full throttle, paused.
I load the flight, press S to change to external view over left wing and then just press p. No winds are set.
As it’s running down the runway I observe the buildings. I can clearly judge here if a driver is bad, if external limiter is causing more stutters (it is…) etc.

I have similar situations for blurries, clouds (some have already tested it).

I have done this test numerous times and if anyone wants, give me a bump and I’ll put the files onto the server.

I have confirmed for myself that an internal limiter with a correct FFTF combo is doing way better job than an external limiter.
Also another user has the same thing, and I believe this is with everyone, just that it’s so unnoticeable, that everyone is just living with it:

Settings Nvidia Inspector:


As I’ve seen this too many times on the forums as of late, users being clever only unzipping the nvidiainspector.exe from the zip and not the whole package, you will have missing descriptions. Make sure you unzip the whole package into a separate folder, otherwise you are going to have missing “Setting Values”.

My settings:


Thanks to Ryan (Tabs) in PMDG forums, we have come pretty close to some conclusions, but there is in my opinion a missing link:
Sparse Grid Supersampling.

Now, if you google and read about it, you’ll find out that it’s very hard on the system but it provides unprecedented quality. One thing everyone is so annoyed by, shimmering, it solves most of shimmering in cockpits and trees/autogen:

2x SGSS not as hard on the system (shimmering reduced greatly)
4x SGSS very hard on the system, especially cloudy situations (absolutely no shimmering)

When it comes to hardware, most middle-to-high end GPUs perform similarly when it comes to FSX. They do not perform similarly when it comes to IQ (antialiasing).

What settings in NI for AA are correct is also dependable on which Nvidia GPU you have.

Hardware-wise, there have been various discussions through the course of more months on which GPU is the right for the FSX.

There have been those who were yelling 560Ti, then some for GTX570 and then some for GTX580. I was one in the last group. Of course, there were some yelling ATI, but let’s not mix here these two, as Nvidia is generally accepted as a FSX GPU.

Until recently, I didn’t really know, or better yet, I was speculating. I was only going according to specs and some of my tests compared to others, but nothing really comparable (there were no tests ran on couple of systems loading one and the same file).

The worst thing though, that our own setup, the FSXMark11, was not able to test this.
I’m talking about the IQ; the relevant settings in the NI.

Some maybe have read the latest posts in the forums where we discussed 560Ti, my cloud situation and the GTX580.

It has been proven, through one simple test, which has so many clouds, that GTX580 performs roughly 33% better than the 560Ti in the same cloudy situation when using 2x SGSS, a setting that many came to recognize as a good middle ground for non-shimmering versus performance.

Now, some might argue if this is worth the roughly double the price of the card. I say yes, because if you think about it for a second: NGX into big airport, cloudy situation: GTX580 30fps, 560Ti 20fps. Of course, these are estimates, but this is one scenario how it could play out: Smooth versus non-smooth.


I would like write couple of word on both cloud and water textures in FSX. There are basically 3 programs out there for as 3rd party textures for stuff like clouds, water textures and some other goodies. FEX, REX and AS2012 are the ones used, with REX and AS2012 being on the top of the list. Those programs offer to install 32bit versions of the textures and quite lovely big resolutions like 2048 and 4096 versions. While higher resolutions are OK to use, depending if your hardware will “eat” them, I noticed there are quite some problems using anything else but standard formats that come with FSX. In FSX, you get by default clouds in DXT5 format and water in DXT1 format. I strongly suggest you keep the DXT5 clouds (of course you can go as high as 4096 if you want, if your performance doesn’t suffer, please test against my cloudtest!) and water should also be kept as DXT1, as I have found problems with NI Anisotropic Filtering (yeah, I know, I’m using FSX one, but there are people insisting on using NI one!)


There are many threads, and always new ones created, with a typical question, what should I buy for the FSX.
FSX is a resource hog. If Battlefield 3, Mass Effect 3, or any other current game is running great, this does not mean that FSX is going to. FSX is an old code, it needs raw CPU power and it needs quite a lot of GPU if you want no shimmering (high IQ)! People tend to forget how important GPU is when getting hardware for FSX.
There is this huge misconception that GPU is not important for FSX and I hope that my previous explanation under Nvidia Inspector managed to shed some light on it.

In this part, we’ll be discussing those hot thread questions like “Build for FSX”, “What is good GPU for FSX” and alike.


Budget oriented: 3570K, 2500K…

Both quite OK overclockers, good all-rounders, as usual IB running hotter than SB…

Performance: 3770K, 2700K…

2700K is a great overclocker, need to turn off HT though to overclock. Same like above concerning temperature.

All Ivy Bridge CPUs have a temperature problems, thus able to overclock less than 2700K, but with improved performance per clock, it reaches same performance like 2700K with slightly lower overclock. The only chance of overclocking IB like SB is to delid it, replace the thermal paste with a better compound (Coollaboratory Liquid Pro).

It basically right now comes to this: if you want to overclock to reach high FSX performance, an overclock is quite recommended or even a must. 2700K can quite easily reach 5.0Ghz or more with a decent cooling. Out of the box, without any modification. Ivy Bridge though, since it is running quite hot, can out of the box reach max. about 4.5Ghz. That will not top the 2700K’s 5.0Ghz performance. Thus:

If you want high performance with a decent overclock, 2700K.
If you’re ready to delid the Ivy Bridge (warranty-loss in any case), then you have good chances of reaching the same 5.0Ghz or even more. Since IB is faster than SB clock for clock, 5.0 on IB are better than 5.0 on SB. But 4.5 on IB are not better than 5.0 on SB.

It all comes down to what you are ready to do with your CPU.

The awaited PCIEx3 is also not a boost in FSX some were expecting it to be.

Check this to get an idea how the performance scales:


This is very important part when it comes to FSX and should be considered when building a computer for FSX. Get a chip that can be overclocked well and get a decent cooling.
Some good sites for overclocking Sandy Bridge CPUs:

And some links for Ivy Bridge overclocking tutorials:
Link2 (video, I think this NCIX guy really explains well)

Most users are running their SB chips around 4.5-4.8. Take that as a pointer.

DISCLAIMER: You and solely you are responsible for your hardware when overclocking.


One of the most asked questions on the forums is “how hot is too hot”.
While everyone is going to have their opinion, there is probably one number that most agree about:
Sandy Bridge should not go 24/7 over 80c (synthetic Prime95 test).
That said, max. operating temperature for the CPU is about 100c, so you should really get worried if you cross 90c, but the hotter it gets, the worse it is for the CPU.
If your synthetic benchmark is going up to 80c, you are most likely not to cross 70c in FSX usage. FSX is never going to load the CPU as high as synthetic benchmarks.
I personally believe that if you keep the CPU cool enough, and if you pump quite a lot voltage into it, you’ll be fine (*disclaimer here that this is only my personal opinion, nothing more).
The usual accepted numbers are up to 1.4 Vcore on the 2500k/2600k/2700k and up to some 80c. (*80c is measured with CoreTemp at high load with Prime95/Linx in a stress test over 1 hour).


Be sure to get known and high performing products.
Good overclocking coolers are:
Corsair H100, Noctua NH-D14 (good for high overclocks on air)
Custom Watercooling (best cooling for home use, short of LN2 and alike solutions)
Scythe Katana 3 (cheaper than those above, for those not wanting to overclock as high as 5.0GHz)
…and many more (too many to count!)

As described above, cooling is not something to look over with ease. Think about it as a way to the high performing computer for FSX.

DO NOT FORGET: a good CPU cooler also needs good supporting case fans. It’s no use if the CPU cooler is good, and it’s fans “cool” the CPU with the hot air stagnating inside the case. See the part about the case cooling.


FSX has no benefit of it and it should be turned off in BIOS.
If you need HT for some other applications, by all means, use it, but do set the correct Affinitymask to force FSX to use all cores but Core0, and no HT cores.


Not a hard choice, currently Z77 series, something like:
Asrock Z77 Extreme4
MSI Z77A-G45

Whatever takes your fancy. All these boards are good, all are going to fullfill the mission. ASUS is to be said to be a great overclocker, take a look at what the board offers in terms of slots and connectors, and see if it’s enough for you. ASUS Deluxe even offers a front bay…


Budget oriented:
8GB recommended
1600 MHz / CL7

8GB recommended
2400 MHz / lowest CL possible / higher RAM clocks

It’s actually very little difference between these when it comes to performance in FSX.
There have been many tests on this topic, and results have shown that RAM has very little impact on FSX. Some say it’s about microstuttering, yet I couldn’t find any proof that the RAM I tested (second) was any faster or caused any less stuttering than the current one I have.
The fact is, if you keep above 1600 MHz and accordingly with the latency, you shouldn’t have any problems.

Make sure though that you get two sticks and not four. More sticks you have, more does the memory controller on the CPU have to work, making more heat, and making your overclocks harder. It has been proven through some tests that the systems were much more stable by usage of 2 sticks when overclocking.

Besides, FSX doesn’t use more than 4GB in any case, and 4GB including all the FSX apps is more than enough for Windows. 16GB is only going to be needed for things like video cutting, professional photography…


This is a huge topic. It has been partly covered in the part with Nvidia Inspector, so I won’t go into much depth here.

Recommended GPU for FSX is currently Nvidia. The most commonly used GPUs currently are from 660Ti up to GTX680.

Mostly used *new* GPUs today are GTX660 /Ti, GTX670 and currently top of the line for FSX, the GTX680. According to many tests, going dual GPU cards, like GTX690 has no benefit for FSX. Only high costs.

Budget oriented: GTX 660
Mid-Range: GTX660TI/GTX670
Performance: GTX 680

There have been tests comparing 580 and 680 series of cards. In geometrical sense in a single screen configuration, these cards perform pretty much the same.
Though, add IQ, and differences can be quite big.

If you check the FSXMark11 results, and find comparable results with similar CPUs but different GPUs, you’ll notice very little difference between these GPUs. This is because FSXMark11 doesn’t test the IQ, the AA settings are default (=weak). So is the picture quality.

Yet my cloud test that was run on couple of computers (which is really hard on card’s IQ), confirmed that these cards scale with up to 33% FPS performance differential. This was compared between 560Ti and 580. The GTX680 gives even higher boost over GTX580 when using high Anti-Aliasing methods like SGSS (4x, 8x). It has been seen that GTX680 is almost 2x faster in clouds when compared to GTX580 and using high IQ, for example 4x SGSS.

Here is the link to the cloudtest:


Unrar this and load in FSX. Press S ONCE to enter external view. Do not unpause.

See what it reads in FRAPS. As a reference, my computer, full screen (settings from above): 26fps. You can use this is as a reference to the cloud performance, which often takes the toll on performance while landing in the bad weather. You are also welcome to post your result below!

That said, it’s up to you to decide which GPU is best for YOU. The more dough, the faster it will be, especially if you like sweet non-shimmering picture with lots of detail!

2xSGSS is going to get rid of most of shimmering, something no other mode is going to do. 4x SGSS goes even step further, and is resolving even the slightest shimmering. So if you want that, there is only one card for you currently: GTX680. Otherwise the performance is going to suffer in heavy overcast clouds.

PCIEx3: in complement with the GTX 670/680, provides no real boost in FSX.


As I have my GPU watercooled, I can hardly report on any normal GPU temperatures or fan speeds. My watercooled GPU never goes much over 45c, even on hard overclock.


Now, this is a huge moot point on the forums. And with right it is.

One thing stands: you should have two harddisks in your system. One for windows and one for FSX.

Budget oriented: HDD
You are going to get the best price/GB ratio. Also if you decide going the HDD way, the best solution right now is the Western Digital Velociraptor 600GB HLHX. It’s big and it’s fast.
Other possibilities include:
Western Digital 1TB Black
Samsung 1TB F3

Performance: SSD

You are going to get the best performance there is.
The biggest plus for the SSD are the loading times. There is virtually no difference while flying. Some say snappier texture loading when changing views, but that’s all there is.
SSD is NOT going to improve your FPS and SSD is NOT going to improve blurries.
Recommendations are OCZ Vertex 3 or 4, Samsung 830, Intel 520… GB? Basically what you can afford, which brings me to…

Most users afford themselves a 128GB one, some more wealthy 256GB ones. And some that really have the dough, ranges of 512GB.
Now, think carefully how big your FSX is, how fast you are going to fill it, and how long until you need a bigger one.

That said, SSDs are also becoming cheaper by the day, it’s only a matter of time until it becomes a massproduct.

A word on RAID: According to some tests I read, RAID setups need to have very good (=expensive) controllers and also fast disks. It has been tested and seen they don’t do much for FSX, in terms of speed. It remained a fact that a single disk, like a Raptor will do much better in FSX than RAID. Not even mentioning SSD. On my own, I never did do any RAID testing.


Do not underestimate a good case. If you are building an air cooled computer, a good case is of big importance.
The airflow is very important and having big and good quality fans for intake and outtake is of essence.
You must consider that when cooling the computer, it is not only enough to cool the CPU, GPU and the main components, but also the mainboard parts, so good airflow over the mainboard is needed.
Thing to consider too is that the case should have some kind of wire management – an ability to hide the cables behind the mainboard, allowing for better airflow.
Recommendations for the cases are:
Corsair Obsidian 650D/800D (medium/full tower)
Cooler Master HAF 932 /X (full tower)
…and possibly some other comparable cases (open for forum suggestions)


You need a good PSU. You are building a good computer, saving on the PSU might only bring you troubles.
If overclocking and a strong GPU are planned, consider getting at least 750w.
If buying a system with two GPUs, consider 850w+.
Also do think of getting a modular PSU, so that you connect only the cables you need, allowing for better airflow in the computer.
Also not a bad idea is to get a PSU with an 80+ Gold certification.
Good PSU companies include Corsair, Seasonic, Cooler Master, SilverStone…

After covering the hardware part, some additional info on some settings:


I hope to be able to update this guide through our shared efforts to make our simming experience a better one, will update it as new hardware becomes available and as long as I see fit.

Suggestions about useful sections are welcome.

I also wish to thank EVERYONE who invented and brought some of these tweaks to light (among others, Jesus Altuve who discovered some of these tweaks, Nick Needham whose guide I used first, before I went into tweaking of my own, Pete Dowson, whose FSUIPC is irreplaceable… and others). I’m just the dude who figured some things out and put it all together.


Updated 680 section in GPU – 21.04.2012
Updated CPU coolers section – 27.04.2012
Added G3D.dll fix section – 28.04.2012
Added Motherboard section – 14.05.2012
Updated CPU and GPU sections with Ivy Bridge status – 17.05.2012
Updated VSYNC section with a new windowed tweak – 04.06.2012
Added UIAutomationcore.dll section for menu crashes – 15.06.2012
Updated FFTF section to explain why 0.2 in some scenarios, updated CPU choice – 25.08.2012
General update&cleanup, updated CPU, GPU sections, added VAS/OOM section, included P3D tweaks used – 02.10.2012
Added water reference section due to P3D compatibility – 06.10.2012
Updated GPU section to reflect SGSS tests with GTX680 – 18.11.2012
Updated Nvidia Inspector Setting section – 23.11.2012
Added new section, Cloud and Water Textures, 14.03.2013
Added new section, Mouse-Cursor FPS Drop, 02.03.2014

1,706 Responses to FSX (and P3D v1.x) Software and Hardware Guide

  1. AZWildk4t says:

    Hi Kosta. Thank you for the valuable information you posted here. I reviewed the changes and applied some of the recommended changes. However, I need some input on improving FPS using PMDG B737NGX and FSDreamTeam KPHX.

    With stock B737 at a standard airport I get 30 FPS. When I load PMDG B737 at same airport, the FPS drops to 15-20. Once I move to KPHX, it drops down to 10-11. I guess this wouldn’t be an issue since it’s really only at the airport and now while I fly the PMDG jet. I am looking for any recommendations to improve FPS for this KPHX and PMDG combo.

    I have an NVIDIA GTX 650Ti with 2GB of memory. Nvidia Inspector shows clock at 928Mhz and usually the GPU is between 30-40%. My computer is a Dell 435MT with an Intel i7@2.67Ghz chip and 16GB of RAM. CPU is usually around 50%.

    So it looks like my GPU and CPU can handle more load but not sure why my FPS is low with the PMDG and KPHX combo.

    Thanks in advance for your assistance.

    • Kosta says:

      If you already tweaked according to my guide, then the numbers seem fine. 2.67Ghz FIRST generation i7, PMDG standalone 15-20 and KPHX with 11fps also seem pretty OK.

      You want to improve FPS? Get a CPU that is capable of running 4.4Ghz+ and a bit better GPU (although GPU is only needed if you decide to run higher levels of antialiasing). Your current CPU, the i7-920 is simply too old and too crappy for FSX. The 2nd generation, 2600K for instance, is way better, there were measurements of 50% more FPS in FSX.

      I’m also very sure that your “50% CPU load” are actually 100% on either Core0 or Core1. And that is your problem.

      Your computer is simply too weak to run PMDG NGX. You should look into lighter addons and/or maybe return to FS2004. I had the same CPU, and I didn’t switch to FSX with it.

      • AZWildk4t says:

        Thanks Kosta. I initially noticed it was showing 8 cores so I turned off Hyperthreading per your recommendation. I do see cases where 2 cores are nearly maxed at 100%. I’m not sure I can do anything to spread the load to the other cores. I’ll look t getting a faster CPU. The best I’ve seen without swapping out motherboard is 3.20Ghz for the LGA1366 socket. If I get a new CPU/Motherboard combo, then my OS isn’t valid and would need to buy another version. I’ll need to make a decision on which direction to go.

        Thanks again.

      • Kosta says:

        You can’t do anything to spread the load. The problem is the CPU, fair and square.
        Don’t upgrade on current mobo. I would recommend you get the 4790 or 4790K, and some Z97 ASUS mobo, maybe Pro (H97 if you don’t get the K version, and you don’t want to overlock). That would be a nice combo. With the K version, you can maybe clock it to 4.7 for additional boost. It would run FSX quite nicely.

      • JMichaels says:

        “Your current CPU, the i7-920 is simply too old and too crappy for FSX”

        Dude, work on your social skills…. you shouldn’t tell people that they have a “crappy” CPU. Saying “Your CPU is not powerful enough for FSX” is much better way to get the message across.

  2. AZWildk4t says:

    Thanks Kosta. You’ve been very helpful.

  3. Max says:

    Hi Kosta! I have testet AA 4x Multisampling+4x Spars Grind+LOD Bias -1.0000! Gives me great performance and absolutly no shimmering! If you want to try it out! Greets MAx

  4. Max says:

    FSX! Yesterday i testet also your settings and 4xS+2x sparse grind! Also very nice! i think my card can handle all of them very well!

    i7 2600
    8gig RAM Corsair 1333
    Geforce 660

  5. Max says:

    Hallo nochmal. Denke du sprichst Deutsch? Habe FTX Global, open lc europe und ein paar ORBX Airports! Was rätst du für eine Fiber frame rate?


    • Kosta says:

      Yes, I speak German, but for the sake of other people who don’t, I keep this blog in English.

      What is a “Fiber frame rate”???? Max, seriously, please read the guide. In detail. I REALLY can’t tell you anything above it, the guide is virtually all I can give you to FSX tweaking without going into long tweaking scenarios myself, for which I really have no time. As some say: time is money. And it really is for me.

      Sometimes I really don’t understand what people think, where they are… I give you a completely free, quite awesome guide (as confirmed by many), a way to understand FSX, and some neither read it nor understand it, and actually dare to ask questions for which I have given a very good explanation in the guide.
      I’m sorry I have to say this, but I find that utterly impolite and unthankful. Maybe I should remove the guide altogether, maybe that’ll be better…

  6. julian says:

    Hi Kosta, very quick question, what would u recommend is the best setting for the max pre rendered frames in the nvidia inspector settings? I’m reading 0, or like the one you have 1, or as Nick has it on his 3? Very confused.. thank you for your input

  7. Henri says:

    Hi Kosta

    I was using your tweaks in Fsx for many years with my old GPU 560ti. Recently I updated my GPU for GTX770 OC Windforce and my frames dropped a lot compared to old one. Is there any ideas what is the problem?

    • Kosta says:

      Apart from testing the hardware properly, did you do the obvious stuff like deleting the shaders, FSX.cfg and tweaking a fresh CFG?

  8. Henri says:

    Thanks for your fast reply. Yes, all done. Bit frustrating, I have been trying to solve this problem for a weeks and still no answer. :)

    • Kosta says:

      What does the 3DMark on the GPU say? Compared it to other cards of the same type? Installed new driver with the option clean install? Reset the profile in CP or NI?

      In FSX though, low FPS don’t often mean GPU. Remember, FSX is CPU intensive. Checked the CPU?

      Unfortunately, there are just so many things that can go wrong, I could spend days asking you stuff like this and still not find it, and it could be just right in front of your nose…:(

      • Kosta says:

        Btw. there was once a veeeeeeeeery weird thing that happened to me: without changing a configuration AT ALL, a friend visited, we flew LOWW-LOWI, and usually at LOWI I have 25fps with the NGX. With him here, it was 8fps.
        Then I rebooted computer, a simple restart, tried the same flight, same result.
        Then I turned it OFF, pulled the plug, waited 5min, booted and tried the same flight, 25fps.
        And no, it wasn’t clouds or anything similar.
        Kill me to know what the cause was.

  9. govind says:

    hey kosta…

    I am back..i have completed my PC installation and everything is working smooth…the game also has a constant fps of 30 at egll with all addons…traffic at 50% (my traffic x).

    I just have an enquiry…how to install nvidia inspector?? i am not able to access the nvidia inspector like yours shown. How to get nvidia inspector so that i can keep settings as yours..

    Also sometimes…the ground textures load a bit slowly..how to change that?? wht might be causing this?

    thanking you

    • Wojtek says:

      Hi, I have the same problem that You did. What did You do, that FSX works fine? :(

      • Kosta says:

        What is the problem that you have? FSX is a big program, the definition of the word fine is a very broad term.

      • govind says:

        hey wojtek….that is there in fsx…the buildings appear with a 2 sec delay as u approach them…similarily…if u have ftx global and all..the 3D lights appear with a 2 sec delay but once they appear..they stay ther…it is normal in fsx…

  10. Steve says:

    If I recall you download a zip file. Just extract all contents to a folder and run the .exe

  11. emann says:

    Dear Kosta,

    in following the tweaks, I am not sure how to set affinity mask with regards to HT – how do I know if this is set to on or off. Also if I set this, do I have to do anything with the AM please. Below is info on my CPU collecting from AIDA64 – so kindly advise affinity 14 or 84?

    CPU Properties
    CPU Type QuadCore Intel Core i5-4670, 3800 MHz (38 x 100)
    CPU Alias Haswell-DT
    CPU Stepping C0
    Instruction Set x86, x86-64, MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2, FMA, AES
    Original Clock [ TRIAL VERSION ]
    Min / Max CPU Multiplier 8x / 34x
    Engineering Sample No
    L1 Code Cache 32 KB per core
    L1 Data Cache [ TRIAL VERSION ]
    L2 Cache 256 KB per core (On-Die, ECC, Full-Speed)
    L3 Cache 6 MB (On-Die, ECC, Full-Speed)

    CPU Physical Info
    Package Type 1150 Contact FC-LGA
    Package Size 37.5 mm x 37.5 mm
    Process Technology 22 nm, CMOS, Cu, High-K + Metal Gate
    Typical Power 84 W

    CPU Manufacturer
    Company Name Intel Corporation
    Product Information http://ark.intel.com/search.aspx?q=Intel Core i5-4670
    Driver Update http://www.aida64.com/driver-updates

    Multi CPU
    Motherboard ID A M I ALASKA
    CPU #1 Intel(R) Core(TM) i5-4670 CPU @ 3.40GHz, 3400 MHz
    CPU #2 Intel(R) Core(TM) i5-4670 CPU @ 3.40GHz, 3400 MHz
    CPU #3 Intel(R) Core(TM) i5-4670 CPU @ 3.40GHz, 3400 MHz
    CPU #4 Intel(R) Core(TM) i5-4670 CPU @ 3.40GHz, 3400 MHz

    Thanks for any assistance.


  12. Eduardo says:

    Thanks for the guide Kosta.

    Does P3D is CPU bond too?

    • Kosta says:

      P3D is very much CPU bound too. There are more stuff on the GPU, but the heaviest stuff like sceneries and virtual cockpits still require very strong CPU.

  13. pilip75 says:

    hi Kosta
    does in Prepar3dv2.3 is it of any use to set on Vsinc when using an AMD R 290x card ?
    Is this setting only working with Nvidia ?
    If i understood well your guide setting, you recomand to set it at 1/2 instead of 1.Is that right?

    • Kosta says:

      P3Dv2.x doesn’t support any external settings for Vsync. The only setting that is working is the ingame one.

      • Ezio Cingolani says:

        Hi Kosta…
        apparently VSync1/2 from NI is working on V.2.4.
        I have Vsync disabled in the P3D menu and enabled via NI and it is working flawlessly..
        (Aero needs to be enabled in Win 7 to have VSync working)..
        By the way, I have just decided to have a look at P3DV2 (on a dedicated drive and system…no intention to switch from FSX at all for the moment) and I have mixed feelings coming from my very first days of using it…I’ll post something after I have find the right balance for my rig. Can you just confirm that P3D.cfg is basically non tweakable in V 2.x ?

      • Kosta says:

        How are you confirming that it’s “working flawlessly”?
        I tried the usual way, and see no difference to v2.3.
        If you are sure it’s working, please describe everything in detail, relevant settings in P3D, NI settings etc.

  14. Paul Ferrughelli says:

    Dear Kosta, Hi.

    I have a new HP 700-215 XT Windows-7 PC with an Intel i7 4790K uP @ 3.6 GHZ, and Nvidia GeForce GTX-745 graphics card with 4GB video RAM, HP 2371 monitor with 1920×1080 native resolution, and 8 GB system RAM. Could you please suggest the NVidia graphics profile for FSX and an example of a fsx.cfg file for my system?

    Thank You,

    Paul F.

    • Kosta says:

      I hope your question is not as nearly serious as it sounds.
      How much are you ready to pay me to do it for you?

  15. pilip75 says:

    hi kosta
    i did not put my question right .
    i mean is it worthwhile to set on, in the Prepar3dV2.3 controls , the Vsinyc control and the associated when using an AMD card ?
    My other question on setting Vsync at 1:2 in NVD inspector is due to the fact that i took advantage of building a new computer around my new i7 4970 CPU + SSD and reloading my programs (FSX,Prepar ext) to test intensively your tweaks.
    I will report soon on my results .
    In accordance, i hope to test also a780TI instead of my R 290X (i feel amd drivers better for multiscreens desk) and i need to known if the correct setting is 1/2 v sync with Nvidia cards .
    and “bravo” again for your very interesting blog .
    p r

    • Kosta says:

      “i mean is it worthwhile to set on, in the Prepar3dV2.3 controls , the Vsinyc control and the associated when using an AMD card ?”
      Well, since I owned an ATI only like years ago and never will own it again, whatever answer I give you, is purely a speculation. I guess it is only worth if you can set your monitor to 30Hz.

  16. Ezio Cingolani says:

    I cannot make a comparison between V2.3 and V2.4 as I purchased P3D2 just a couple of days before 2.4 was released, so I can say that I started with 2.4.
    I had read somewhere that Vsync could only be enabled by the sim menu but in that way I had a significant hit in FPS and smoothness, so I disabled it in the P3D menu and tried enabling via NI (version, with 344.11 drivers, my card is a GTX680). I didn’t use a dedicated profile for P3D but just the Global_Driver_Profile, selecting Standard and 1/2 refresh rate, using the EVGA precision X frame limiter to keep 30 FPS.
    I can confirm that it works…absolutely no tearing, and much smoother that the P3D menu Vsync.
    What was the problem with V 2.3 ?

    • Kosta says:

      The fact that you have no tearing is no confirmation that VSYNC is working. The only way to be sure is to unlock the FPS everywhere, turn on external vsync, and if your monitor is 60Hz and your setting is 1/2, then your FPS *must* lock to 30fps. Then and only then is VSYNC working.
      I will go through your procedure, however I’m already sure that it won’t lock the P3D, because it currently simply doesn’t support it. There is no driver profile and there is no exclusive full screen. Without either of those two, it cannot work.

      • Ezio says:

        OK….if this is the case, then I must say that it DOES NOT work, as if I unlock FPS everywhere and use 1/2, my FPS do not stay locked at 30 (this is indeed what I have in FSX where I do not use any limiter, use the NI at 1/2, my FPS are unlocked but they actually stay at 30…). Apologise for the confusion… :-) . However, the fact that the way I am using the NI settings for Vsync produces no tearing and almost zero FPS impact, while using the P3D internal setting is almost a show stopper, still remains a good solution for the moment..
        Just one question….What do you mean with “..there is no esclusive full screen..” ?

  17. KPluxz says:

    Hey Kosta I’m planning to follow this awesome guide and apply it to a new build. I want to ask thou if it is enough with a i5 4670k CPU on a Z87 chipset or is it worth it upgrading to i7 and Z97?? I’m really looking for price balance too. Also the GPU I’m aiming for is a GTX 750/TI. Will a 600W PSU do the job??

    Beforehand thanks and I’ll be happy getting your advice , happy flying! :)

  18. REVEN says:

    Hello Costa

    First Bravo would love to conditions on investment you can help me

    As soon as I put the file FSX CRG [BUFFERPOOLS]
    Poolsize = 0 / Usepools = 0 I get flashes areas and areas less than
    My computer’s spec I7-3970EX O / K 4.4GHZ -16GBMEMORY DDR3 1600MHZ
    SSD512GB – 680GTX EVGA 4GB I did the test on my GPU reaches a maximum
    Although I do not understand why this is happening because it is strong enough video card
    Airport FLYTEMPA OMDB no flashes at all, but other ports and some just have a lot of

    I’d love to be able to help me out im

    Thank you

  19. Lloyd says:

    Hi Kosta,
    I’m planning to upgrade my Pc from the current specs below:
    i7-3770K CPU (OC) 4.5GHz quad core air cooled with Thermalright 140mm True Spirit Fan
    ASUS EVGA GTX 780 3.0GB
    2×8 Gb 1600Mhz Vengeance DDR RAM
    1700Watt Sesonic PLATINUM 80 Plus PSU
    2Tb Seagate HDD (7.2k rpm)
    P8Z77-V PRO Motherboard
    Fractal Design DEFINE R4 Case

    I have already bought i7 4790K and just waiting for the Corsair H100i liquid cooler to be delivered ..
    Do I need to change my current motherboard Asus P8z77-v Pro since I will be overclocking or that one would be ideal..?

    Also from your guide above regards Fsx settings how can I tell if HT is on coz I need to redo Fsx settings and Fsx.cfg using your tweaks..? I have been suffering from a lot of OOM’s lately and need help with configuring the VAS to 4Gb dedicated to Fsx..

    Thank you

    • Kosta says:

      I don’t quite get your questions.
      If you are asking me if P8z77-v Pro support 4790K? Why not check that yourself? I am not a wikipedia, sorry man!

      “need help with configuring the VAS to 4Gb dedicated to Fsx..”
      This sentence makes no sense really. If you understand how VAS works, then you would know there is nothing you can do to configure the VAS. It is a “pot” as I call it. When the pot is full, it spills.
      If you are suffering from OOMs, install less into your simulator. That is the only cure.

  20. Dear Kosta,

    what do you think about the Affinity Mask parameter inside Prepar3D v2.x (specifically v2.4)? I read extensively about no tweak is “useful” for Prepar3d, but wtihout it I have so many stutters (with a i7-4770k, overclocked to 4.2GHz). With an entry like this one: AffinityMask=84 (HT ON three cores active, 1 to 3, 0 is “free” for o.s. processes), my Prepar3d come back to life, without stutters anymore. I would try another AffinityMask=252 (logic cores work beside the physical one)… but I wish to understand better what’s the logic behind these codes (is an active HT useful or not?) and why they are almost mandatory for a new product as P3Dv2.x.

    Thank you!

    • Kosta says:

      If your sim runs better with 84, by all means use that. Currently, for me, performance is better with no AM.
      P3D, just like FSX, still has fibers on the 1st core, so that can’t be moved, and two reasons to use AM were to separate it from most of windows processes (although Win7 does pretty good multi-threading, so it is possibly a futile try) and to separate main thread from the fibers, as I explained in my guide.
      Whether to use HT or not, is up to you. HT does does nothing for P3D, but is important for things like video-encoding and other HT-enabled applications. P3D is not one of those. It produces more heat, which means lower overclock, usually.

  21. Paul Ferrughelli says:

    Dear Kosta, Hi.
    You certainly are a spicy individual, right to the point. Thank you for the offer.
    Sincerely, Paul

    • Kosta says:

      Hi Paul,
      Don’t take me wrong, but your question implies me tweaking your computer. Me working for you.
      And yes, always been direct and honest.
      What I offer here is a collection of tweaks and changes, explaining how to implement them. For free.
      I don’t intend to tweak other people’s computers in my free time – I would rather spend it with my son, my family or flying.
      Single questions which are possibly not covered, I answer gladly.
      All the best

  22. Raul Ortiz says:

    Servus Kosta.
    Thanks a lot for your guide. My FSX has never looked better and performed smoother.
    I was looking for this since long ago.
    Thanks a lot!!!!

  23. Remco Blom says:

    Dear Kosta,

    I’m not really gonna bother you with any questions since i’m fully capable to apply your tricks and test it to the max. I want to thank you for your research and hoping that there will be more testing with P3D. This P3D software is still under development and i’m willing to buy it, since FSX is a old and error-sensitive program.

    Keep up the good work!

  24. ezio cingolani says:

    Ciao Srdan,
    following my initial trials with P3Dv2.4, I have come to the conclusion that, as I had already read somewhere, P3D.cfg is basically untwekable (as a matter of fact I am running it with zero tweaks). Overall the performance is pretty good but I cannot get rid of the stutters during taxi expecially when turning. This happens regardless of the P3D complexity settings. The questions is : Is it inherent to P3D itself or is there a fix for this ? (fyi I have an I72600K @4.8 and a GTX680).


    • Ezio,

      few days ago I asked Kosta about the same topic. Check above… the AffinityMask solved for me the same issue.

      • ezio cingolani says:

        I followed your suggestion for AM but the results did not get significantly better, so I suspect I must be overstressing the system somewhere else (even though my P3D settings are not very “aggressive”).
        Can you advise, if possible, your other settings ?

  25. pilip75 says:

    hello Ezio
    i used Prepar V2. with a I 2600K at 4.7 Mhz and a R290X and now V2.4 with a 4970 k at.4.7 mhz and a 780Ti with kosta tweaks said to work on Prepar and i have and never had such problem, even when i used a non tweaked Prepar
    But Alessandro advise sound good .
    good luck !
    P R

  26. ezio cingolani says:

    Thanks guys..!
    I am usually not so lazy and check the previous posts before writing…but this time I completely missed Alessandro’ s post above…..thanks for pointing it out..!
    I’ll follow his suggestion and see what happens..

  27. Bas says:

    Hi Kosta,

    Months ago I thanked you for your tweaks and that every usefull tweak is collected on your site ….till I found this tweak: Disablepreload. When I want to change a plane of location in the menuscreen I sometimes waited voor more than 45 seconds or longer to get into the menu, due to that FSX is loading the default flight in background. This tweak fixed it and now I just injoy FSX without frustration :)

    So: If you wish to disable the pre-load of the default flight when FSX starts up, add this:

    Something to add at your site?

    • Kosta says:

      Interesting. I have this tweak in my CFG for a very long time now, I must have missed it in the guide. Been using disablepreload since like forever, probably since it was discovered or suggested.
      I will maybe add it to the guide when I get more time, cuz right now I’m barely at home, at my son is also a priority!

    • Emann says:


      in which section of the cfg file do you enter this tweak please?


  28. Ezio, I’m currently working with an i7-4770k OC 4,3 GHz and a nvidia gtx 670. With proper software, I noticed a high usage of core 0 with Prepar3D v2.x, with disfunctional running (i.e., stutters) during turning, takeoff and landing. My proc is HT enabled but with Kosta’s suggestion, I’ve maintained all cores threaded (for applications that use them properly), all but P3D. For this reason my Affinity Mask is 84: core 0 is free, all the job is for cores 1,2,3, without HT actually unused (you can reach a more stable OC with this settings). No more to do… I haven’t other mods in my .cfg.

  29. ezio cingolani says:

    Maybe a little bit off topic, but I want to share this with you. As per my posts above I am trying to run P3D V2.4 at an acceptable compromise between performance and visuals.
    I run P3D and FSX on the same computer (I72600K @4.8) but on two completely separate Windows 7 installations (and drives). Whilst AM=14 is one of the “classic” tweaks in my FSX.cfg, on FSX I have never used HT ON as I know it doesn’t bring any added value and it may even make things worse (and I can confirm this is true also in my experience). I have been running FSX for a few years now with very good results thanks to the great Kosta’s guide and tweaks.
    What happened now is, following Alessandro’s advice above, I enabled HT on the BIOS and added AM=84 on P3D.cfg, but, focusing only on P3D performance improvement , I completely forgot to replace AM=14 with AM=84 in my FSX.cfg, with the result that I ran FSX with HT ON and AM=14. Guess what ?, FSX has never run so well. I totally ignore the rationale behind this and I know this is against all technical explanations given so far on this subject. I tested the same FSX configuration with HT ON and AM =84, but it was not as good as with AM=14. I checked on Performance Manager and saw that three cores are running almost 100% loaded but the other 5 have a very little utilization. The only downside is an increased thermal load (average 8 deg more than running with HT OFF), but this quite normal with HT ON.
    I don’t want to reopen a new discussion on HT ON vs OFF, because thousands of words have been already spent on this subject, but I thought this eventual yet interesting experience was worth a feedback to everybody and it could be interesting if someone could replicate this on their system..

    • Kosta says:

      Many thanks for your experience-report. I’ve tried many times what you did. Many times. Without visible, measurable or placebo difference.

      • ezio cingolani says:

        I do believe you, indeed, and actually I didn’t mean to experiment anything new, expecially something that I know wouldn’t work…(I have stopped playing around with cfg for ages now..thanks God..!)..I just noticed that eventually, as I wrote above, and I was quite surprised to find it out…
        By the way, going back to P3D V2.4…..do you think a GTX680 is a good card or is it undersized for running P3D well ?
        have a nice day…!

      • Kosta says:

        I think the GTX680 is quite slow for P3D. I am now getting the 980, I believe it should kick ass on P3D, but time will show.

  30. karl says:

    hi there im haveing a complete knightmare with all of this lolol my spec is fx 8 core 3.8 asus borad 16 gig verguance ram gtx750 card i personaly think this is more than enought to get good results and also a SSD and it just looks crap auto gen is slow i have orbx global and pdmg 737 also rex overdrive please please could you help me as you guys really know your stuff thank you

    • govind says:

      set your fiber time fraction to 0.33 and check..

    • Kosta says:

      “i personaly think this is more than enought to get good results”
      Well, I am sure if you personally think that is more than enough, then it probably is!

      But, as govind said, if you simply copied my tweaks over, without reading and understanding what they do, you most likely set FFTF to 0.1 or abouts, and you have problems with autogen. Setting it to .33 will most likely help, however it will also bring FPS down. To be able to use my tweaks, you need to have GTX 760 or preferably stronger, including a high-clocked Intel CPU.

      This is exactly what happens when people come over and simply just enter my settings into the CFG :/

      • govind says:

        hey kosta..

        I too accidentally set my FFTF to 0.28…..and always saw tht my autogen appers with about 1-2 sec delay…even my traffic..and my fps was constantly at 30…in any severe condition…so i read through ur forum and found the culprit..FFTF !!! so i set it back to 0.33(FSX default) and believe me….all my autogens and traffic are perfectly there..they dont have any delay in loading and it looks very realistic…:D

        Now about fps…again i really dont notice any drop in my fps even after increeasing FFTF…except that while turning it just goes down to max 28 for a fraction of a sec…but definitely u can live with that…after all its a simulation..:D
        cheers to u again for the wonderful explanation…


      • Kosta says:

        Yes, it will return the autogen if the balance is not correct. The balance is all that matters. For instance, if your CPU can take the beating and is clocked high, the lower you will be able to lower the FFTF, the more FPS will you get in the sim, if you are CPU limited. It all hangs in a balance and effects one another. This is why I preach about balance so much, it is basically the only thing to take care of, once you balance it out correctly, you will get the best performance possible. And it’s hard, real hard.
        I am glad for anyone who read this and made their sim work better, that’s all.

      • govind says:

        yes kosta..u r perfectly correct abt the balance..i have a i7 4790K cpu running at 4.5GHz ( no overclocking..only turboboost…) and without reducing the FFTF from 0.33 itself..i am able to get constant 30fps..and tht is more thn sufficient i feel….although at EGLL or KSFO…where the traffic is relly high and with lot of airport details…..i get a drop of fps to 25(only in virtual cockpit)..i can live with that..because in locked spot view and all…i am getting again constant 30fps even in EGLL! I am happy in tht way…

        kudos and happy flying…
        govind :)

  31. Cleciano Diniz says:

    Kosta hello, i have a problem … I set up the computer and the configuration is as follows: Nvidia GTX 780, DDR4 (2400 Mhz), i7 5930k, Antec PSU 1000, 240 Gb SSD, two 3 TB HDD, and this unique PC for FSX, but my disappointment is huge because the antialiasing is not working, I use Nvidia Inspector and I’ve done all possible settings and I can not get the aircraft and scenery are great quality, please help me, the what should I do?

    PS .: I use DX10 Fixer

    • Kosta says:

      Well, in my guide I explicitly specified that I’m not using DX10. One of the problems that it brings is the AA-problem.
      That said, I can only tell you that I got AA working if I turned on AA in the sim and set NI accordingly. But please, look at the DX10 resource sites, don’t ask me.

  32. Cleciano Diniz says:


    Thank you, I have to then use DX9 and content myself with it only if I want to get a better picture …

  33. Jon says:

    Hello Kosta.
    I have cpu i7 3770k
    I used your guide from beginning, 6 months flying with no problem. I had overclok to 4.4. Now I went to 4.7. One simple question, do I need to recreate new CFG file for FSX in order for FSX to see new 4.7 overclok?
    Thanks Kosta!

  34. John Orfanos says:

    Jon hi, no need to recreate the cfg file. There is a good chance you could push the FFTF a bit lower though to get better frames as a result of the CPU boost.

  35. b247ng says:

    Hi Kosta, have you tested new DSR? There could be someting with this new nvidia driver and DSR option, at least for 1920×1080 displays. You probably know about it, i tested some settings with lower nvidia inspector settings and higher resolution, and it works pretty well, but i need to test it with fully loaded FSX when i have time

    • Kosta says:

      Yes, I have tested it, with both FSX and P3D. I’ve actually written my opinion on it on P3D forums extensively, but to be brief, I’ll say I think it’s nothing else but SGSS. What it does is also basically the same. It renders in higher res, then it downsamples.
      I’m looking forward to testing it on the GTX980, as the experience there might be different. We’ll see.

  36. Jon says:

    Thank you for answering.
    Last question acording to FFTF
    I had for 4.4 value of 0.10 if I go to 0.1 it’s the same value or lower?
    or the value of 0.01 is the lowest possible?
    Just I mixed up with this and want to know if there is a difireents between 0.10 and 0.1 in CFG.


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