GTX 680 2GB is better overall @1600p according to tom's hardware review. Who cares how much memory it has ?! What really matters is real word results.

As for compute performance, how many people seriously care about that ?! HD7970 might have advantage in this, but GTX 680 has advantage it other areas such lower power consumption, 4 display support and PhysX support. Not to mention that nvidia usually have better driver support.

Kepler is a revolutionary architecture. It performed better than what was expected. It beats AMD with smaller die size and lower power consumption. However, AMD fanboys will never admit this.