GeForce GTX 460 SLI vs. Radeon HD 5970: Two Against One
 

As you know from our news and reviews, AMD’s superiority in the sector of single-processor gaming graphics cards has been challenged by Nvidia releasing its GeForce GTX 480, yet the AMD Radeon HD 5970 is still unrivalled as the best dual-chip solution, carrying two RV870 Cypress processors on board. The GeForce GTX 480 fails to compete, largely due to its lower texture-mapping performance, but AMD’s solution is superior to its opponent in the rest of technical specifications, too. However, there is not doubt Nvidia wants to challenge AMD here as well, so the development and release of a dual-processor card with Fermi architecture is just a matter of time and technical ability.

Nvidia had serious technological obstacles until recently because the hypothetic dual-processor GeForce GTX 490/495 would turn out to be too hot and power-consuming even if based on a GeForce GTX 470 SLI configuration, let alone GTX 480 SLI. So, although a pair of GeForce GTX 470 cards working in SLI mode could deliver the desired performance, the GeForce GTX 490/495 was still not feasible. But now that Nvidia has its new, simpler and more economical GF104 core, the situation is completely different. This rather inexpensive GPU is a much better building block for a dual-chip gaming graphics card than the monstrous GF100. Our tests showed it to be competitive to the GeForce GTX 470 at increased clock rates, and a pair of GF104 chips in a SLI tandem looks impressive even at the reference frequencies

http://www.xbitlabs.com/articles/vid...tx460-sli.html