Originally Posted by AaronP
I agree. Speculating wildly, it's possible that something IceWM is doing was previously unaccelerated and is now performed on the GPU. Normally that would be an improvement, but if the GPU is bogged down running compute work it might end up slower.
I don't think IceWM is at fault here. Previously I was running Window Maker and had the same experience. Even if I'm not logged in in the WM, X is really using a lot of CPU time while doing CUDA work. This was previously not the case as I mentioned in my first post. X used to use a max of 30% of CPU time on my previous version of openSUSE which was 11.3. After upgrading to 12.1, X started to consume a lot. The only way I was able to stop this is by completely turning Accel off which gives you a very slow experience in any WM (but this is not an issue for me)