A couple of weeks ago, we looked at a single Radeon HD 4870 X2 board to see how AMD's flagship graphics offering performed, and today we go one step further by pairing up two of these boards in a CrossFireX configuration. Four GPUs, a total of 4GB of graphics memory, and 4.8 teraflops of computing power - Sounds impressive, no? Join us as we see just how that theoretical behemoth stacks up in the real world.