Performance recap
Although individual game results are obviously worth looking at when you want to gauge performance in a specific game, we have also calculated a performance index based on all tests with the same weight for each game. We set an index of 100 to the Radeon HD 7870:

[ 1920x1080 ] [ 2560x1600 ]The Radeon HD 7970 GHz Edition gives an overall gain of 10% over the standard Radeon HD 7970, whether at 1080p or at 2560x1600. It has a 12% lead over the GeForce GTX 680 at 2560x1600.
This performance gain gives the Radeon HD 7970 GHz Edition the lead over the GeForce GTX 590 by a short head on average and allows it to close the gap on the Radeon HD 6990, consigning the previous gen bi-GPU to history.
Note that at 1080p, the GeForce GTX 680 is on equal terms with the Radeon HD 7970, while a few weeks ago, during our test of the GeForce GTX 670, the HD 7970 had the advantage. This improvement can be explained by the fact that Nvidia has finally corrected its performance problem in Total War: Shogun 2.