AMD Radeon HD 5870 + 5850 CrossFire Analysis

"One thing that shocked me was that the CrossFire gaming performance of a Radeon HD 5870 + 5850 was lower than that of a pair of Radeon HD 5850 video cards in CrossFire in all of our testing with the exception of one game. I would assume it is because the higher capacity card (the Radeon HD 5870) gets brought down to the lower one (the Raeon HD 5850) plus some overhead. This basically goes to show that while mixing and matching video cards to run CrossFire works for better performance it isn't the route to take for peak performance. If you want the most from a CrossFire configuration it is clear that you should pair two identical cards together."