Starting with the aging Doom 3 game, there wasn't much in the way of performance changes up until the 12.11 Beta. Unfortunately with this latest release, the performance didn't move in the right direction. Catalyst 12.11 for Linux is noticeably slower than the driver releases from earlier in the year.
There wasn't too much movement out of the Lightsmark OpenGL lighting benchmark.
Nexuiz saw some fluctuation between driver releases but in the end its OpenGL performance from Catalyst 11.12 to 12.11 Beta was close.