[Myxir]

Well... It's strange.
My current situation is like this:
The desktop resolution is 1280*1024. I want to play Regnum in1280*1024 in windowed mode because I can't switch to the other workspaces then. I told compiz to disable windowdecorations for Regnum. That works fine so far.
I found out that shadows draw the big part of the performance in that resolution. If I disable them I almost have the same performance as in 1024*768 with shadows. It's around 50 FPS now when moving in a small group.
But like every second start I just get a black screen. Just the interface elements are rendered.