Radeon 7770 Crossfire problem

[kboth18]

Hello all, this is my first post and am brand new to the pc gaming community. I'm currently helping build a friends computer, who has been into computers for longer than I, and we are having some difficulty getting crossfire to work. The rig has http://pcpartpicker.com/mr/newegg/gigabyte-motherboard-ga970ad3p this motherboard and http://pcpartpicker.com/mr/newegg/amd-cpu-fd6300wmhkbox this cpu. He is using an older Asus 7770 2gb that he has had for a while, and a recently second hand acquired AMD branded 7770 2gb. Both video cards have been tested and work but with the crossfire bridge it doesnt appear as though it is using the second gpu. Im wondering if the PCI-E express slot speed may be the issue? The board has 1 x16 and 1 x4 express slot and we are wondering if that second slot (x4) might be the cause of the issue? the board is crossfire capable and the gpus are compatible from what ive seen. Also crossfire is enabled on the pc. 

 

Sorry for the wall of text, and i appreciate any help.

 

Thanks, Kevin