Well lately I'm hearing alot of guys having bad performance even when using 8 series card. By following these steps orderly I hope some of your issues will be solved. The Unreal Engine has had a long history of being a highly tweakable engine. These tweaks worked for me and plenty of others. So lets get to it.

-First thing first is to make sure all your drivers are up to date.

-Next simply click on Start. Now click on Documents. Browse and click on My Games. Next click on Gears of War for Windows. You should now see Binaries, Engine and WarGame. Click on WarGame and then Click Config. In that directory search for WarEngineUserSettings and open it using Notepad(Make sure your security allows you use your files as a Administrator else you will be prompt that these commands wont be executed. To do this simple right click on the Gears of War for Windows and select Properties. Click the Security tab. You should then see User names and Group names. Now click Edit to configure settings for the User/Group name. Next simply search for your computer name and select it. Under Permissions for _________ check all the tabs for Full control ect and select apply then ok.) In the notepad you open for WarEngineUserSettings search under System Settings for 'OnlyStreamInTextures'. It should say OnlyStreamInTextures=FALSE. Change FALSE to TRUE and save. This tweak should eliminate the low frames and stuttering.

Some people have reported by clicking Start then clicking Games and right click and 'Play' Gears for Windows crashing will eliminate.

For those that want to go further with tweaks follow along.

If your a Soundblaster X-fi user copy and paste these text under [ALAudio.ALAudioDevice] to your WarEngineUserSettings using Notepad.

UseEAX=True
Use3DSound=True
UseDefaultDriver=True
MaxEAXVersion=5
UsePrecache=True
MaxChannels=128
MaxEAXVersion=5
CompatibilityMode=False
UseFilter=True
UseReverb=True
TimeBetweenHWUpdates=10
UseEffectsProcessing=False
DeviceName=
LowQualitySound=False
MusicVolume=0.3
AmbientVolume=0.6
SoundVolume=0.6
VoiceVolume=1.0
DopplerFactor=1.0
Rolloff=0.5
OutputRate=48kHz

It should then look like this:

[ALAudio.ALAudioDevice]
UseEAX=True
Use3DSound=True
UseDefaultDriver=True
MaxEAXVersion=5
UsePrecache=True
MaxChannels=128
MaxEAXVersion=5
CompatibilityMode=False
UseFilter=True
UseReverb=True
TimeBetweenHWUpdates=10
UseEffectsProcessing=False
DeviceName=
LowQualitySound=False
MusicVolume=0.3
AmbientVolume=0.6
SoundVolume=0.6
VoiceVolume=1.0
DopplerFactor=1.0
Rolloff=0.5
OutputRate=48kHz

If your soundcard is a audigy ect, then these tweaks are usable however you have to know which Eaxversion your card supports and simpy change MaxEaxVersion to whichever your cards supports. Also you should know how many amounts of channels your card uses. Since I'm a X-fi user my card supports 128. If your cards supports 64, 32 and lower change MaxChannels= to whichever your card supports.

Quadcore users can add these texts to your WarEngineUserSettings to see if you get a performance increase:

[Havok]
HavokNumThreads=4

Dual core users should change to 2.

There has been some new tweaks I discovered and while I'm still observing to see if there helpful your more then welcome to try to them to see if it helps you. Add these texts to your WarEngineUserSettings.

[D3DDrv.D3DRenderDevice]
UsePrecaching=True
UseMipmapping=True
UseTripleBuffering=True
UseGammaCorrection=True

If your not using Vsync then I don't recommend using the 'UseTripleBuffering=True', you can simply delete it.

I hope some of these tweaks can can ihelp you guys. Check to see updates for this blog post. Enjoy...