Quote Originally Posted by Draxx View Post
I have similar issues, under XP I can bench and game fine at 800Mhz core, but in Vista mainly "White Out" and the COJ DX10 benchmark I have to lower the core to 776Mhz otherwise I get artifacts.

maybe it's the DX10 "part" of the chip..... ????
It's card load simply. DX10 loads and stresses the card more than DX9. If you run something like ATITool artifact checker, you would probably get artifacts at 800 Mhz both in XP and Vista.