i have a EVGA 256-P2-N567 7900GT KO Superclocked 256MB, PCI-E x16, Dual DVI. this card has since then been put into legacy. now i want to run the card in sli but i thought you had to have two of the same card. so my question is can i get a different brand 7900GT like BFG etc. and still have them work in SLI correctly?