We've seen tests of dual 7970s in CrossFire simulating a 7990 and ASUS released the ARES II which was the closest we had until today with the release of the reference HD 7990.  There are many reviews to chose from when looking at this new flagship card, such as from a pure performance perspective such as [H]ard|OCP's which did not come out well for AMD's new card.  If you are more interested in our new Frame Rating process then there are two reviews to read, one that deals with the 7990 on the publicly available driver and perhaps more interesting is a prototype driver provided to Ryan that is intended to fix Crossfire stuttering on single displays but not for EyeFinity

"Today marks the launch of AMD's Radeon HD 7990. The Radeon HD 7990 is a dual-GPU video card that has its two GPUs down on a single PCB that uses CrossFire to operate the two Radeon HD 7970 GPUs. We will test this video card in the latest games, comparing it to GeForce GTX 680 SLI and Radeon HD 7970 GHz Edition CrossFire. "

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