I’ll be blunt: the AMD Radeon HD 6990 is a beast. Soundly outpacing the best that NVIDIA has to offer (at the moment), this dual-GPU juggernaut — previously codenamed “Antilles” — clambers to the top of our graphics card heap by serving up the most raw power we’ve seen to date. But then there’s the price: at $699 (as of 3/8/2011), it’s strictly aimed at those ultra-enthusiasts who’ll spare no expense on their gaming rig.

But rest assured, you’re arguably getting your money’s worth — provided you’re already living luxuriously on the bleeding edge. The Radeon HD 6990 is pricey, but it proved to be demonstrably faster than its closest competitor, the $500 NVIDIA GeForce GTX 580. For comparison’s sake, I also included the $350 AMD Radeon HD 6970 — the company’s recent single-GPU speed champ.

The “Cayman” GPU debuted in AMD’s 6900 series, in the aforementioned Radeon HD 6970 graphics card. The Radeon HD 6990 combines a pair of these GPUs onto a single card — think Crossfire, on a stick. The end result is a powerful graphics card that fits comfortably into a single PCI slot (though the card is two slots wide), leaving plenty of room for a second…

• READ MORE (Source): AMD Radeon HD 6990 Review – PCWorld