[Andris6000]

I wouldn't turn off vsync, especially if you are using trackir. I will cause image tearing. Turn off supersampling- use multisampling. At that resolution you probably don't need to have your antialiasing or anisotropic filter so high. Try turning down the AA first.
Try these settings in your config.ini;

[Render_OpenGL]
TexQual=3
TexMipFilter=3
TexCompress=2
TexFlags.UseDither=0
TexFlags.UseAlpha=0
TexFlags.UseIndex=0
TexFlags.PolygonStipple=1
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=1
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=2
Forest=3
LandShading=3
LandDetails=2

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

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

PolygonOffsetFactor=-0.15
PolygonOffsetUnits=-3.0

See if that helps. Good luck, mate.

I tried turning down AA and Antistropic . I turned it down to multisampling too .
Now I have antistropic on 8 . AA on 4 and your config settings .
The game actually has worse framerates now ...
I seriously don't know how is this even possible .