Video card manufacturers have included overclocking utilities in their drivers. ATI calls their utility OverDrive. NVIDIA has a registry hack cooled Coolbits. With Coolbits enabled I was able to overclock XFX's card to 584MHz for the core and 1.628 Ghz for the memory, an over 20% overclock of the core speed over XFX's factory overclocked card. The 7900GS was completely stable at that speed, meaning there's some room in this core. I think its pretty amazing how far graphics cards can overclock today.
Standard clock
Overclocked
When overclocked, the card is over 10-20% faster in the four benchmarks I chose: 3DMark06, 3DMark05, Oblivion and FEAR. I chose Oblivion because its one of the more beautiful games available today. I chose Quake4 because it is one the better metrics of OpenGL performance available at the moment. The 3DMark scores should be very close to the theoretical maximum correlation to the unoverclocked scores scene on the previous performance pages.
Oblivion
Quake 4
3DMark 06
3DMark 05
