Overclocking

Nvidia supplied us a new version of EVGA’s precision overclocking tool for use with the GTX 680 2GB and we found overclocking to be a fairly straightforward experience. Three sliders allow you to increase the card’s power draw above its stated 195W by up to 30% for a total of 253W, but increasing this alone won’t automatically overclock the card. Remember that the stock GPU Boost curve tops out at 1,110MHz.

To tap into those extra MHz you’ll need to increase the GPU offset, which raises the entire GPU Boost curve. By increasing the card’s power allowance to 120% we were able to increase the GPU offset by 100MHz, resulting in a base clock of 1,106MHz and maximum boost clock in Unigine Heaven of 1,210MHz. We were able to push this higher on occasion, but were not able to achieve a stable overclock with an offset higher than 100MHz regardless of power draw. Of course, every GPU is slightly different and your mileage may vary.

For comparison sake, we’ve pitched the GTX 680 2GB in its stock and overclocked guises against both dual GPU graphics cards, and the HD 7970 3GB in its stock and overclocked settings. The HD 7970 3GB overclock is running at 1,125MHz, with a memory frequency of 1.575MHz (6.3GHz) while the GTX 680 2GB is running with a base clock of 1,106MHz, boosting up to 1,210MHz, with a 1.5GHz (6GHz effective) memory frequency).