Gainward GeForce GTX 680 Phantom Review
 

On paper, the GTX 680 has almost 200% more shader performance than the GTX 580, roughly 250% more texture performance, 90% more ROP performance and 100% more memory bandwidth. With the Radeon HD 7970 only being ~9% faster than the GTX 580, AMD appears to have priced itself into a corner this time around.

http://www.techspot.com/review/525-g...force-gtx-680/