I have a problem running IL-2 in perfect with sli enabled.

When I run on just one video card (I have 2x8800gt's) everything is smooth in perfect, but with SLI enabled there is a heartbeat like micropause. There is also a nasty flicker of shadows on the water.

Turning off perfect mode in SLI also cures these problems.

I have seen this problem reported by people here and there, but never any solutions.

I have tried all the .dll's.

I don't believe this is hardware specific unless it is to the 8000 series cards. I have 3 different machines that all do the same thing.

This machine is a Q6600/680i/4gb ram/2x8800gt setup, also have;
-Dell M1730/2.8ghz cpu (sorry, can't remember which one right now), 4gb ram/2x 8700M GT
-amd 6400+/Nforce 590/4gb ram/2x8800gts 640mb (the older ones)

I have tried several different drivers, all do it to some degree. Maybe you have one that works?

This is really annoying, I can get 60+fps most all the time in SLI, but must put up with this unacceptable stuff, so end up taking the hit and running one one card.

Here is my ;

[Render_OpenGL]
TexQual=3
TexMipFilter=3
TexCompress=0
TexFlags.UseDither=1
TexFlags.UseAlpha=0
TexFlags.UseIndex=0
TexFlags.PolygonStipple=1
TexFlags.UseClampedSprites=0
TexFlags.DrawLandByTriangles=1
TexFlags.UseVertexArrays=1
TexFlags.DisableAPIExtensions=0
TexFlags.ARBMultitextureExt=1
TexFlags.TexEnvCombineExt=1
TexFlags.SecondaryColorExt=1
TexFlags.VertexArrayExt=1
TexFlags.ClipHintExt=0
TexFlags.UsePaletteExt=0
TexFlags.TexAnisotropicExt=1
TexFlags.TexCompressARBExt=1

TexFlags.TexEnvCombine4NV=1
TexFlags.TexEnvCombineDot3=1
TexFlags.DepthClampNV=1
TexFlags.SeparateSpecular=1
TexFlags.TextureShaderNV=1

HardwareShaders=1

Shadows=2
Specular=2
SpecularLight=2
DiffuseLight=2
DynamicalLights=1
MeshDetail=2
VisibilityDistance=3

Sky=1
Forest=3
LandShading=3
LandDetails=2

LandGeom=2
TexLarge=1
TexLandQual=3
TexLandLarge=1

VideoSetupId=3
Water=4
Effects=2
ForceShaders1x=0

PolygonOffsetFactor=-0.15
PolygonOffsetUnits=-3.0
[DGen]
CampaignMissions=Hard
RandomFlights=3
CampaignLength=Medium
AirIntensity=High

I am running at;

[window]
width=1680
height=1050
ColourBits=32
DepthBits=24
StencilBits=8
ChangeScreenRes=1
FullScreen=1
DrawIfNotFocused=0
EnableResize=0
EnableClose=1
SaveAspect=0
Use3Renders=0

Any ideas?

Cdr
Edit/Delete Message

May not help, but it might: be sure that you use Split Frame Rendering SLI mode. IL-2 chokes under the Alternate Frame Rendering SLI modes. The SLI mode is set using the advanced setting in the nvidia driver control panel. (Unfortunately, SFR is usually the default for IL-2 but it's definately worth checking). Good Luck!

I had a weird 'perfect' water artifact when running SLI that was well known: it looked like a beam of light shown across the water's surface, sort of like a sunset effect. I never could figure out why or when it would appear.

Post your entire conf.ini and also you dxdiag report.

I got 2 8800GT cards running in SLI and everything runs like a dream and looks amazing now.

Make sure in the NV control panel, under 3D settings for the game you set Highest Qualety and everything else should be the NV recomended settings.

Only thing you change is you set AA to 16xQ, Override Aplication settings for AA and set Supersampling. (mines all in dutch but you figure out what i mean)

Here is my OpenGL bit of the Config.Ini file.

[Render_OpenGL]
TexQual=3
TexMipFilter=3
TexCompress=0
TexFlags.UseDither=0
TexFlags.UseAlpha=0
TexFlags.UseIndex=0
TexFlags.PolygonStipple=0
TexFlags.UseClampedSprites=0
TexFlags.DrawLandByTriangles=0
TexFlags.UseVertexArrays=1
TexFlags.DisableAPIExtensions=0
TexFlags.ARBMultitextureExt=1
TexFlags.TexEnvCombineExt=1
TexFlags.SecondaryColorExt=1
TexFlags.VertexArrayExt=1
TexFlags.ClipHintExt=0
TexFlags.UsePaletteExt=0
TexFlags.TexAnisotropicExt=1
TexFlags.TexCompressARBExt=0

TexFlags.TexEnvCombine4NV=1
TexFlags.TexEnvCombineDot3=1
TexFlags.DepthClampNV=1
TexFlags.SeparateSpecular=1
TexFlags.TextureShaderNV=1

HardwareShaders=1

Shadows=2
Specular=2
SpecularLight=2
DiffuseLight=2
DynamicalLights=1
MeshDetail=2
VisibilityDistance=3

Sky=2
Forest=3
LandShading=3
LandDetails=2

LandGeom=2
TexLarge=1
TexLandQual=3
TexLandLarge=1

VideoSetupId=17
Water=4
Effects=2
ForceShaders1x=0

PolygonOffsetFactor=-0.15
PolygonOffsetUnits=-3.0



P.S. My specs are: AMD X2 6400+ BE, NVidia NF590 SLI, 2x 8800GT, 8GB EPP DDR2-800.

Thanks guys, I am on the road for a week or so.

I will give NDS_Camp.'s settings a try when I get home and give report.

Cdr