OK this might sound funny but I've reverted to older drivers. Very old... 10.1 to be precise!
I had been running 10.10e, then I installed the Sims 3 and the game wouldn't load no matter how many game-related fixes I tried - the sound would start looping, then
everything would freeze either with the loading game on the monitor or with a black monitor. Ctrl-Alt-Del wouldn't work and I'd have to hard-reboot my machine.
I updated to the latest drivers (thinking they would correct the problem, but they didn't...) and worked back from there. Interestingly enough the game worked fine with 10.1 and previous drivers (9.x etc...)
While happy I had that particular game running, I also played Fallout New Vegas while on the same old 10.1 driver. Now FNV had been giving me problems. The game used to run fine but while using VATS (it's kinda zooming in while shooting) my fps had started dropping to 1 or 2. Imagine getting 1 fps in an rpg shooter using a 5970...
I had originally given fault to the latest game patch.
BUT - running Fallout New Vegas on the old 10.1 driver resulted in a flawless game
-- vsync'd always 60 fps occasionally dropping to 55, whether I'm in the VATS zooming mode or not.
Since FNV is my favourite game (and I haven't finished it yet) I'm not going to try any new drivers -- if it works don't try to fix it lol