My system:
Windows 7 64bit
i7 2600k HT unlocked
16gb ddr3 1600mhz
XFX Radeon HD 5870 XXX 1GB GDDR5
2x WD HDD in RAID0

Installing the AMD hotfix and updating drivers from 11.8 to 11.9 is what rendered the game unplayable for me. The flickering and artefacting were the biggest problems.
After uninstalling the drivers and the hotfix and reverting to 11.8, the game runs flawlessly with the texture pop-in being the only problem. Not idea YET, but playable and I can wait for a real fix.
Just thought I'd share for any AMD users out there. Try Catalyst 11.8


EDIT: I apologize, I just read 2 other threads with this same information in it. Mods may delete if they feel it necessary.