I have been trying to find out about the new 780i and 790i motherboards and whether they can have 3 9800GX2 cards in 3 way SLi?? because effectively you will end up with 6 cards :)
Yes u can have 3, but even quad sli scales horribly, trust me, i had it...so 3 9800gx2's would be a complete waste, grab two 9800gtx's or 260's...or 2 4850's or 4870's
