AMD Radeon HD 7970 is the first video card based on a 28nm GPU. It is the first member of the Southern Islands also and by extension the first video card to implement GCN (Graphics Core Next). The HD7970 is the first card that's compatible with the next version of DirectX, 11.1, which will be added into Windows 8 next year.
Specs:
How Fast It Is?
Radeon HD 7970 is 31% faster than the Radeon HD 6970, and that is in a game that does not stress the video cards much these days. The newer games seem to show the most improvement. Batman really stands out as showing a large difference using DX11 and Tessellation. Next to that, Deus Ex: Human Revolution was the second largest game to benefit with the HD 7970. That game also uses Tessellation. Third to that was Battlefield 3. These are some large performance improvements over the Radeon HD 6970.
When looking at the Galaxy MDT GeForce GTX 580, the Radeon HD 7970 looks a bit less impressive. Keep in mind, our Galaxy MDT GeForce GTX 580 is clocked well over a standard or reference GTX 580, but also costs more than the Radeon HD 7970. Price wise, the Radeon HD 7970 is $50 cheaper than the Galaxy MDT GTX 580. At its worse, we saw only a 9% improvement in Batman at single-display, but that increased to 19% at 5040x1050. The game to benefit the most was Deus Ex, which was 29% faster on the HD 7970 at single-display and 38% faster in Eyefinity. That is the largest improvement we saw in our testing over the Galaxy MDT GTX 580.
Sources: Anandtech and Hardocp