Sundowner
Maybe try to get rid of the water shader? I know it's not used on medium settings, but who knows?
[WaterTextureMaterial]
UseEffectShader=TRUE
EffectShaderName=WaterEffect.fx
DepthBufferCheck=TRUE
DepthBufferWrite=FALSE
RenderedInOrder=TRUE
AlphaTestEnabled=TRUE
CullMode=NO_CULL
LightEnabled=TRUE
SpecularEnabled=TRUE
EmissiveEnabled=FALSE
FogEnabled=TRUE
AmbientColor=1.000000,1.000000,1.000000,1.000000
DiffuseColor=1.000000,1.000000,1.000000,1.000000
SpecularColor=1.000000,1.000000,0.900000,1.000000
SpecularPower=1.000000
ZBufferOffset=4.000000
BlendOp=BLEND_SRC_ALPHA
NumTextureStages=2
TextureStage[01].TextureName=
TextureStage[01].MipMap=FALSE
TextureStage[01].FilterEnabled=TRUE
TextureStage[01].StageColorOp=DIFFUSE
TextureStage[01].StageAlphaOp=TEXTURE
TextureStage[02].TextureName=ref_color.bmp
TextureStage[02].MipMap=FALSE
TextureStage[02].FilterEnabled=TRUE
TextureStage[02].StageColorOp=TEXTURE
TextureStage[02].StageAlphaOp=DIFFUSE
set to UseEffectShader=FALSE or comment both lines out
Edit:
I see Deuces lurking -maybe he will help