I installed the 220.127.116.11-pclos1.bfs kernel and when I booted it couldn't run the proper dkms fglrx because there was also the proprietary driver source from ATI installed, along with the newer one from the repositories, so I manually ran dkms and installed that module (it's the same that's running on the stock 2.6.32 kernel). When I rebooted compositing won't work on KDE4 when running either kernel - it's no longer supported. The backup Xorg.conf file doesn't show me the problem; it's hardly different from the current one. There have also been some strange configuration loses in KDE4. Looking at OpenGL in the KDE Info Center, the 3D Accelerator and module are unknown. I think that's the clue. Shouldn't that be Mesa? And yes, I have rebooted a few times.