The results of the AMD Radeon HD 6990 are purple in the diagrams; the AMD Radeon HD 6970 is red, the Nvidia GeForce GTX 590 is blue, and the Nvidia GeForce GTX 570 is green. Due to time constraints the cards were only benchmarked at their default frequencies.
Since we already published a review of the Radeon HD 6990 in which we benchmarked the card at 830 as well as 880 MHz and found that these two modes did not differ much in terms of performance, the Radeon HD 6990 will be used in its accelerated mode here. This is relevant because some AMD partners still offer the warranty for the card even if it's used in the accelerated mode. We guess there will be more such vendors in the future.
The new dual-processor card from Nvidia is faster than its AMD counterpart in the FSAA-less mode and at low resolution. The difference is smaller in the high-quality mode at 1920x1080. At the same time, the dual-processor AMD flagship is as good as the Radeon HD 6970 tandem even though its memory frequency is lower by 500 MHz. The GeForce GTX 590, on its part, is somewhat slower than the SLI tandem of two GeForce GTX 570s. The new dual-processor card from Nvidia is clearly limited by its reduced clock rates and can't compete with the two GeForce GTX 570s, let alone GeForce GTX 580s.
The Radeon HD 6990 is the better of the two dual-processor cards in the new 3DMark 2011 although the gap from the GeForce GTX 590 isn’t large. Otherwise, we’ve got the same standings as in 3DMark Vantage.
Unigine Heaven Demo
This test is won by the GeForce GTX 590 which enjoys a 24% advantage in one of the test modes. The gap between the two dual-processor cards is smaller in the FSAA mode, yet Nvidia remains in the lead. As opposed to the two previous tests, the Radeon HD 6990 is somewhat slower than the Radeon HD 6970 tandem which boasts excellent scalability in CrossFireX mode in this test. We must also note that the GeForce GTX 590 is slower than the GeForce GTX 570 tandem, too.
The Radeon HD 6990 goes ahead in Crysis. The dual-processor graphics cards are both somewhat slower than the respective CrossFireX and SLI tandems.