FSX FPS Guide
Posted by jackfolla on March 30 2007 00:35:59

Introduction

This week saw the release of Microsoft's latest and greatest, Flight Simulator X. I know many of PMDG's customers rushed out to the store to buy it and returned home only to be met with a near slideshow of sub 10FPS performance. I had the same initial reaction, but took the time to apply various tweaks and try different slider settings and I've arrived at a very workable level of performance that will hold me off until new hardware comes into the market in the next year that will allow us to run it maxed.

Here's what I've personally done to make FSX run reasonably well on my machine and on Capt. Randazzo's, which is nearly identical to mine.

Specs

Here's my PC's specs. I have a pretty nice machine and you're gonna have to make adjustments yourself to compensate if you have a lower end system.

I'm running a dual-core Athlon 64 X2 4200+ on an Asus A8N-SLI motherboard (nForce 4 chipset), 2GB of low latency PC3200 RAM, and a GeForce 7800GTX 256MB video card.

General system tweaks

One problem I constantly see among all gamers (not just FS users) is a lack of tweaking and optimization in Windows itself before the game/sim is ever run. You can't possibly expect good performance when you've got 20 system tray icons and their associated programs running, a bunch of potential spyware/malware slowing the machine down, and year old drivers that don't have all the latest optimizations and bug fixes.

Run a spyware scan

Spyware has become an absolutely insideous threat to many computer systems. If you are not absolutely dilligent with your Internet and email habits, you've probably picked at least some up.

I recommend using these free scanners:

Install them, update their definitions and run all three with a full scan, removing anything they may find.

Visit Windows Update

I'm constantly amazed by the number of simmers who refuse to install Service Packs and Windows Updates. These aren't going to slow your machine down, break FS, or anything like that. Windows XP Service Pack 2 is an absolute must - you are opening your system to all sorts of malware threats if you aren't running it.

Permanently disable unnecessary startup programs

I prefer to do this manually and permanently since the types of things listed here shouldn’t be running at any time on your machine. Software makers have gotten into a terrible habit of installing all sorts of junk that runs at startup that you absolutely do not need.

  1. Download a copy of Autoruns and extract it to a folder of your choice. This is a very advanced tool that lets you see exactly what is loading at start up and from where. The guys that wrote this are among MS's top Windows engineers and know every possible way that something can load automatically on your machine.
  2. Open up Autoruns and go to the options menu and check "Hide Microsoft Entries" and then hit the refresh button. You're now looking at a detailed list of every bit of third party software that's loading at start up on your machine. Go through the list and uncheck useless things like Real Player, Quick Time, iTunes, Adobe Reader Speed Launch, etc.

IF YOU ARE IN DOUBT ABOUT AN ITEM, DO NOT DISABLE IT!

There is a searchable list of startup programs availiable here at SysInfo where you can look these items up. You can also right click the item in Autoruns and select "Google..." to automatically perform a web search on the name of the file.

Temporarily disable necessary startup programs

This is what you want to use Ken Salter's famous FSAutoStart utility for. Set up a profile for FSX in it and temporarily turn off things like anti-virus monitoring, real time defrag engines, search indexers like Google Desktop, etc. Anything that could sit there and suck CPU cycles away from FSX, take up RAM, or thrash the hard drive while flying you want disabled while using the sim.

As before, if you're in doubt about an item, just search for it on SysInfo or Google as in the earlier example.

Update your drivers

This is absolutely critical.

You should have the latest drivers for these pieces of your hardware at a bare minimum:

Driver Cleaner can assist you in fully removing old versions of drivers which can conflict with the new ones you're installing. Be sure to fully remove the driver and anything else related to it from Add/Remove Programs FIRST before rebooting in safe mode and running Driver Cleaner.

Motherboard

CPU-Z is a very useful tool for determining which motherboard chipset and processor you have - run it and look on the Mainboard tab for details on which chipset you have.

CPU

Many of the newer CPUs have a driver that can improve performance and power management. This is particularly true of the AMD Athon 64X2 Dual Core series. Intel CPUs do not currently need a driver.

Video Card

Sound Card

Other hardware like mice, keyboard, joysticks, etc are not as critical but you should still try to keep their drivers up to date as well. Go to the manufacturers website for those.

Defrag

When I installed FSX, I defragged both before and after the install. I’d assumed that the files would not be fragmented post install, but I was wrong – they were and very much so. Fragmented files (especially textures or terrain BSP files) can cause a lot of stuttering and longer than usual load times. Run the MS defrag utility at the very least and preferably a commercial defragger like:

I personally use Perfect Disk 8 and find it to be the best one on the market. Be patient, the post FSX install defrag took almost an hour for me.

Other general resources

The best general source for information on setting up and tweaking a gaming PC that I have ever seen is Koroush Ghazi's exhaustive 175 page TweakGuides Tweaking Companion. TweakGuides.com is a great site and I highly recommend checking out his other guides if you play any of those games in addition to FS. You'll learn a ton about graphics card terminology and your games will run a whole lot better too!

FSX Tweaks

Ok so first here's the tweaks I've used that are actual modifications you need to do outside of the sim.

Please note that I did not develop these tweaks – most of them I gleaned from the AVSIM FSX Forum, from the various ACES team member blogs, and from Matt Fox’s website.

CFG tweaks

The FSX.cfg file can be found by default in C:\Documents and Settings\(Your Windows User Name)\Application Data\Microsoft\FSX on Windows XP and in C:\Users\(Your Windows User Name)\Application Data\Microsoft\FSX on Windows Vista - I suggest making a shortcut to it on the desktop and setting Notepad to open .cfg files by default.

Fiber Frame Time Fraction

Find the [MAIN] section of the .cfg and add the following line:

FIBER_FRAME_TIME_FRACTION=0.33

This line controls how aggressive the sim is in ensuring that scenery loads in quickly. Without this line, you may see the dreaded “blurries” more frequently. 0.33 is the recommended value by the ACES team, but you can experiment with raising or lowering it as you see fit. The range is 0.0 to 1.0 and higher values will mean more priority to scenery loading and less FPS.

Texture Bandwidth Mult

Find the line that reads

TEXTURE_BANDWIDTH_MULT=40

And change it to

TEXTURE_BANDWIDTH_MULT=400

This will make texture load in while flying go much faster.

Buffer Pools

Add the following section and line to the end of the cfg file

[BufferPools]
PoolSize=5000000

This is a sort of scenery cache that will help eliminate a lot of the stuttering you see when panning the view around the cockpit or outside the plane. It does increase video memory usage though, so this probably won’t be effective on a video card with less than 256MB of memory.

Autogen Density

Add the following lines to end of the [TERRAIN] section of the .cfg

TERRAIN_MAX_AUTOGEN_TREES_PER_CELL=4500
TERRAIN_MAX_AUTOGEN_BUILDINGS_PER_CELL=3000

These are the default settings for how many buildings and trees appear in each FSX scenery cell. I personally have not changed these, however I’m including the tweak here for those with lower end systems to try out.

This sets the maximum number of autogen objects you’re going to see with the slider at Extremely Dense (full right). It’s a multiplier on the entire slider, so if you lower or raise these numbers it will affect all settings on the slider, not just the maxed out one.

Autogen Tweaks

It’s rather clear that autogen is the prime source of most of the low out-of-the-box performance in FSX. There are a couple tweaks that I used to get it under control.

AutogenDescriptions.spb

Matt Fox noticed a few days after FSX release that the sim tries to load a huge variety of different tree models at random when it renders forests. This places a large strain on current systems. He created an alternate AutogenDescriptions.spb file that trims down the number of choices FSX has when drawing a forest. This made a huge difference in FPS for me.

To apply this tweak, download the file here: AutogenDescriptions.spb

Now go to your FSX/Autogen folder and rename the default AutogenDecriptions.spb file to AutogenDescriptions.bak for backup purposes. Now copy Matt’s new file into the folder.

default.xml

This is the other important autogen tweak and many will probably remember this one from FS9’s early days:

Go to FSX/Autogen and rename the file default.xml to default.bak

This turns off the “custom” autogen buildings such as gas stations, fast food restaurants with big chickens out in front etc. MS supposedly fixed the FPS loss from this in the FS2004 9.1 patch, but it appears that the problem may be back in FSX. Disabling this file makes the world look a little less realistic in high density city areas, but I think the tradeoff for increased FPS is well worth it.

Other Tweaks

There are other more extreme tweaks available on Matt’s page involving reduced quality textures etc. but I did not use these and don’t recommend doing so unless you have a low end system and are still experiencing FPS issues after applying the listed ones here.

Greg German has also created a really nice PDF tweak guide of his own that you can check out as well.

Sliders

Here’s how I’m running my sliders:

Press Custom on the main settings screen to get the options in the screenshots:

Graphics Tab

Image:Fsxgraphics.jpg

Note here, if you’re running dual monitors like I am, you need to pull down the list and select the 2nd monitor – set it to exactly the same settings as the primary one.

AA and AF – I leave these unchecked and then force them on via the Nvidia driver. I have no idea what the in-game settings are actually doing if you enable them, so I like to retain control with the driver. I set trilinear in the sim because Anisotropic (AF) is just an addition on top of trilinear by definition, so it seems like the best thing to set when you’re adding the AF with the driver.

Light Bloom – this is a massive FPS hit for me, cutting it almost in half, so I have it disabled. This is unfortunate because the effect is very cool.

Aircraft Tab

Image:Fsxaircraft.jpg

I have aircraft self shadows off here because I noticed a slight FPS hit from having them on and they don’t work correctly on my card due to what’s probably a driver issue. (new drivers haven’t been issued since the FSX release)

Scenery Tab

Image:Fsxscenery.jpg

38m is the mesh resolution I ran in FS9, and it seems to work well here. You can lower the texture resolution if you have an older video card, but I see no issues with 1m on mine.

The Shader 2.x water is a big FPS hit at the upper range of the slider, so I’ve left it on Low 2.x. I honestly think it looks more realistic on low anyway – the higher settings are too reflective for my taste based on what I’ve seen on real flights. Land detail textures is the setting adds the bump/normal mapping effect to the terrain. I suggest leaving this on if you can because it looks a lot better. The sim will look more like FS9 if you turn this off.

For my system, the Dense Autogen setting is the right balance between detail and performance. Higher settings showed a lot more FPS loss for me.

Ground Scenery Shadows is an FPS hit just as it was in FS9 so I’ve left it off.

Weather Tab

Image:Fsxweather.jpg

Pretty basic here – the weather system is largely unchanged from FS9. The notable exception is the lack of an overall visibility slider, since MS has changed the way visibility works (it is much much better) in FSX.

Traffic Tab

Image:Fsxtraffic.jpg

I have air traffic disabled for now. It caused some FPS degradation with it on and I’m waiting for Ultimate Traffic to get updated anyhow... I do however leave the cars and boats on to some degree because I think they look cool and add a lot to the immersion factor. Putting the cars up to 100% causes a noticeable FPS drop so I’ve backed it off a bit. Adjust to suit your tastes.