SLI/Perfect 'Heartbeat'

[Cdr84]

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