After some time playing (usually 1-1.5h) this graphical bug occurs:
If I exit game screen with alt-tab, graphics turns to normal again. And after while, hour or so later problem occurs again and becomes unrecoverable.
It is not gpu overheating issue because my gpu temp stays bellow 70c.
I still haven't tried patch 1.02 and new drivers for video card.
Other than that, game works fine, good framerates with everything on normal/high, viewdistance 2500, fillrate 150%.
E8400
4GB
GTX275
Win XP sp3