turn fastwrites off, there's seems to an issue with the 6800's and nf3 boards(stuttering/freezes) disabling fastwrites helped solve that issue for me. also i'm guessing you have a DFI nf3, also it's best to cange your AGP aperture to 128. my 6800nu(16/6) ran smoother at 128 compared to 256. with a good overclock and your card being unlocked you should score well over 4400 in 3Dmark05