http://www.hardocp.com/article/2012/07/ ... ng_redux/1
From the conclusion
" The highest stable overclock with voltage on the MSI GeForce GTX 680 Lightning using the default BIOS had a significant performance increase compared the overclock without voltage tweaking. In Max Payne 3 it was 8.9% faster than the overclocked MSI GeForce GTX 680 Lightning without voltage tweaking and 14.1% faster than the stock video card. BF3 Singleplayer the highest overclock was 16.1% faster than its stock settings. In BF3 Multiplayer it averaged 74 FPS and was 9.8% faster than the overclock without voltage tweaking, and 15.3% faster than the stock video card. In Batman it was 7.7% faster than the overclock without voltage tweaking and 14.5% faster than the stock video card. In The Witcher 2 it was 8.9% faster than the OC without voltage tweak and 14.3% faster than the stock MSI GeForce GTX 680 Lightning.

Basically, the performance increase between the overclock with and without voltage tweaking was higher than the performance increase the stock MSI GeForce GTX 680 Lightning experienced from the overclock without voltage tweaking. In other words, voltage tweaking provided over double the performance increase compared to the overclock without voltage tweaking.

With fans at 100% the GPU temperature on the default BIOS increased to 62c using voltage tweaking.

The LN2 BIOS had an even higher overclock which pushed the GPU extremely close to 1400MHz, and put the memory over 7GHz GDDR5. In MP3 it was 8.1% faster than the Overclocked AMD Radeon HD 7970 and 18.1% faster than its stock settings. In BF3 SP it was 4.3% faster than the Overclocked AMD Radeon HD 7970 and 17.9% faster than the stock MSI GeForce GTX 680 Lightning. In Batman the overclocked MSI GeForce GTX 680 Lightning was 16.2% faster than its stock settings, and 19.3% faster than the Overclocked AMD Radeon HD 7970. In The Witcher 2 it was 2.4% faster than the Overclocked AMD Radeon HD 7970 and 14.3% faster than the stock settings. The overclock on the LN2 BIOS increased the performance above the Overclocked AMD Radeon HD 7970 in every game.

With the fans at 100% the GPU temperature on the LN2 BIOS increased to 73c using voltage tweaking and 300% Power Limit. "
This is indeed a beast

This is what i predicted in my GTX 670 article about overclocked Kepler vs overclocked Tahiti and it has come to pass from the HardOCP conclusion:

The only issue is that it is $600