One AOA Forums' members, Samuknow, has written a guide on using NiBiTor to hack your nVidia GeForce 6- or 7-series video card BIOS to change the voltage settings.
"Over-clockers are always looking for a way to squeeze every last drop of performance out of their hardware. This has been going on for years.
Today’s Video Cards are great candidates for over-clocking. Many have high-end capabilities just waiting to be released.
As any over-clocker knows, an increase in voltage can sometimes net a moderate to great increase in the overall over-clock, but there is no
guarantee that this mod will offer any increase in your over-clock. With that in mind, we will be showing you how to perform a BIOS volt
mod to your 6 or 7 series card."