Well, I have a XFX Geforce 7800GT; and I can simply not get it to OC. Even with "Detect Optimal Frequencies" it won't work properly. The temps are fine, I just get artifacts every time. I even lower the frequencies after detecting optimal, and it will work at first; but artifacts will appear eventually. The highest I've seen the temp get with OC is 49C, so I don't think that's the problem; any ideas?