AMD’s dual GPU cards have come a long way in the past several years. The original Radeon HD 3870 was noisy, ran hot and didn’t always perform up to snuff. Since then, AMD’s Catalyst Driver suite has substantially improved the performance and breadth of CrossFire-supported games.On the hardware side, AMD is pulling out all the stops with its Radeon HD 6990 card. The company understands that a dual GPU card is most appealing to a small band of enthusiasts who really want the card to push the edge of the envelope, both in terms of engineering and features.Despite being fully twelve inches long—like its predecessor, the Radeon HD 5970—the HD 6990 looks a little less imposing than the 5970. Maybe it’s the center-mounted fan, which visually breaks up the huge mass of the cooling shroud.