hello , i got low fps when i use crossfire and to my surprise with just one graphic card i got very good fps (all games are running better with 1 graphic card). I asked a lot of people and they told me that is possibile to one card is running on pci x8 and the other one is running on pci x16 and i should change both to x8 from bios. The problem is im really nab in bios and i have no ideea how to change this.
In bios i only found : http://img580.imageshack.us/img580/1570/130110221934.png
I have x2 amd radeon hd 7770
Motherboard : ASUS : F1A75-V EVO
ps : sorry for my bad english