Ok, I'am quite sure I miss something but can't figure out what. I just moved to a new case and would like to start OC'ing the 8800 a bit. I've opened RivaTuner -> Driver Settings -> System settings -> check the OC option -> performance 3D mode. Now when I move the bars the "Test" button below should become clickable if I remember correctly. I can click apply with the moved bars (520/800) but nothing happens, the monitoring still shows standard clock speeds (513/792). Using ForceWare 158.45, Vista 32bit, uninstalling/reinstalling driver/RivaTuner did not help, any suggestions? Dynamic fan profiles are working by the way.