I believe that what you have to do is to open up the 3DFX controls program that you used to overclock the card in the first place and hit "Confirm Changes". If you don't confirm, it will always reset the card back to the factory defaults the next time you reboot- a safety net in case the computer locks up when you try and run it with the higher overclock. Hope this works for you! Hopefully yours will do better than mine... admittedly mine doesn't have any active cooling on the chip (other than a desk fan blowing over it), but I can't get it to run stably at anything over around 155 without locking up in UT after 3 or 4 games... methinks I should invest in a Borb- or mount the spare Pentium HSF I have to it....