"At AMD we pride ourselves on both the excellence of our products, and in the integrity of our messaging," Dave Erskine, Senior Public Relations Manager for Graphics Desktop at AMD, said in a statement. "So now I issue a challenge to our competitor: prove it, don't just say it. Show us the substantiation."
AMD argues that Nvidia's statement is baseless. The company said it combed through Nvidia's announcement "to understand how it was that such a claim could be made and why there was no substantiation based on industry-standard benchmarks." The chip giant argues that since Nvidia did not reference an industry benchmark such as 3DMark 11 in its press release, it cannot possibly say that the GTX 590 beats the Radeon HD 6990.
TechSpot has reviewed both graphics cards. You can read our take at the following links: AMD Radeon HD 6990 Review: Sumptuous Dual-GPU Power and Nvidia GeForce GTX 590 Review: Dual-GPU Wars. Here's a relevant excerpt from the latter's Final Thoughts section:
It's impossible to conclude the GeForce GTX 590 is faster than the Radeon HD 6990 as it really depends on the game, and that's precisely why we test with fourteen titles now. Based on our findings, the GTX 590 was just 1% faster than the HD 6990 on average. The GTX 590's only big win was in Far Cry 2 and some argue that the game isn't a worthy test candidate given the large influence Nvidia had on its development.
If we removed Far Cry 2 from the results, we would actually have the GTX 590 to be 2% slower than the Radeon HD 6990. It's also interesting to note that a vast majority of the GTX 590's losses were in DX11 titles: S.T.A.L.K.E.R.: Call of Pripyat (-15%), Metro 2033 (-20%), Battlefield Bad Company 2 (-9%), and Aliens vs. Predator (-10%).
In short, the cards are both quite close, but AMD insists that only its product has the right to be crowned king. Hopefully Nvidia won't ignore its main competitor and will issue a response.