ASUS ENGTX275 Review
 

To get the most out of any video card, you have to keep it cool! With that rule in mind and not having an LN2 pot hanging around, the only option I had was to increase the fan speed to 100% to keep the ENGTX275 as cool as possible during testing. After bumping the fan speed up, I started by pushing the GPU core up in 20MHz steps until it would lock up in testing. I followed suit with the shaders and memory to find their limits. Once the limits were found, it was a matter of getting the three parameters to work together. I ended up with solid increases on all three speeds. 731MHz on the core is a 98MHz increase over the stock 633MHz. The shaders offered a bump of 124MHz and the memory was the big winner with a huge bump of 172MHz. This overclock delivered solid increases in performance allowing this card to deliver performance almost equal to that of the ENGTX285 TOP, a factory overclocked card also from ASUS.

http://www.overclockersclub.com/reviews/asus_engtx275/