I use the precision tool for clocks, all I use the ATI Tool for is it's artifact scanner. If I don't trust ATI Tool's results, I'll run a few instances of FurMark, or one of the 3DMarks and see what happens too. Precision is the only utility I've used to clock my GTX 260 thus far! Aside from NiBitor 4.3, which does support and properly ID/Read GTX 200 BIOSes. Nvflash 2.67 seems to properly backup and flash GTX 200's also.