I just recently installed double powercolor 6870's as crossfire. My system has,amd fx 8150 8 core cpu,16 GB 1600 Mhz ddr3 ram,Asus crosshair Formula V Mainboard and 120 G SSD HDD , 2 TB Sata2 HDD and these 2 Ati 6870 cards. You might think this set up smooth works like glider but no. It has tarrible performance on games as GTA 4 , Crysis 2, Skyrim and so on. Any idea why is this happening and how to fix it?