I have
extremely bad performance with my system (Intel i5 2500k, Radeon 6950 crossfire, 8GB RAM)

tested 12.3 today and absolutely no difference. When driving at Spa I have 60-70 fps when I have no other car in front of me. But if there is maybe 2 cars in front of me my fps is 30-50. When driving out of the pit its about 20 fps but feels like 10.
Starting a race is impossible, because at the start grid its like 1 frame per second and I crasch immedialtely. It won't work any better if I turn Crossfire off either. I know it's just beta so i hope it get better, it have to. With my system and the graphics of this game, there should be no problem to drive with max settings. Now i have some high, some medium. AA level 3 and MXAA off...