It is really confusing at the moment, I tested all combinations and cannot get Sacred Gold or Enemy Territory to work "playable" with the open source drivers. X + composite (xcompmgr) works in each combination (worst with fglrx/ati-drivers). glxgears for each combination:
2.6.31 + mesa 7.6 + ati-drivers = ~1200 fps
2.6.32 (KMS) + git mesa + git libdrm + git xf86-video-ati = ~300 fps
2.6.31 + mesa 7.6 + xf86-video-ati-6.12.4 = ~600 fps
//edit: what I even didn't mention, with ati-drivers 9.10 the fans spin up every few seconds noticeable, with 9.9 the fans are quiet -.- with the open source drivers this doesn't happen...

