so far I've seen people reporting the following chipsets to be affected, but there may be others intel 910 intel 945 intel 965 ati 3450

ATI HD3200 (IGP part of the 780G chipset) with the free radeon driver and 2.6.35.2 doesn't quite work with the KDE compositing. With opengl compositing when moving windows they disappear, and X freezes often too (only the mouse and ctrl-alt-Fx works). -- damjan