I have this motherboard, using 6870s in Crossfire. I have a Phenom II x4 975 in it, and can run Battlefield 3 on Ultra with a good frame rate. If you already have this board, it works perfectly fine in Crossfire. You may get a few more frames on a board that supports an x8 slot instead, but if you don't want to buy a new motherboard this one works quite well without any issues.