Extremely odd behavior with IL2 yielding very poor performance

[nearmiss]

You might try these settings

[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=0
TexFlags.TexEnvCombineDot3=1
TexFlags.DepthClampNV=0
TexFlags.SeparateSpecular=1
TexFlags.TextureShaderNV=0

HardwareShaders=0

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

Sky=2
Forest=0
LandShading=3
LandDetails=2

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

VideoSetupId=17
Water=0
Effects=1
ForceShaders1x=0

PolygonOffsetFactor=-0.15
PolygonOffsetUnits=-3.0

TexMipFilter=2
Specular=1
SpecularLight=0

You might want to go over to ubisoft community help --> http://forums.ubi.com/eve/forums/a/frm/f/49310655

and post your dxdiag printout as well.