No problem here with my Asus 5970, OCed and watercooled. My Asus was flashed with the Sapphire OC bios.

But it was impossible to install 9.12 Hotfix over 9.11, no matter what I did. Deleting with DriverCleaner or manually, nothing was working. But 9.12 directly over 9.11 went smoothly. Then 9.12 Hotfix over 9.12 without any problems.

I've played over 12 hours in the last 2 days at Dragon Age, Resident Evil 5 and Torchlight, without a single crash, bug, shimmering BSOD or any other problem.