(Image credit: Tom's Hardware) 15 years ago, AMD released its powerful Radeon HD 6990 graphics card (review link). This flagship dual-GPU hot rod, codenamed Antilles, was several months late in March 2011 and poked its head out only a couple of weeks before Nvidia’s reply. Nevertheless, the dual-Cayman XT GPU board, with a majestic-for-the-era 4GB of VRAM, became the world’s fastest graphics card (though that was an honor AMD already held with the Radeon HD 5970 2GB ). To reach this PC performance pinnacle, AMD perhaps pushed the silicon a little too hard, though, with reviews of the time complaining about heat, noise, and power consumption. (Image credit: Tom's Hardware) The specs and performance of the Radeon HD 6990 were spectacular to behold at the time. Two fully-fledged Cayman XT GPUs were shoehorned onto a single PCB and connected via AMD’s CrossFireX.…