You have 7 slots on the back of the case, so i would say 3-way, which is also where i'll say the performance caps, the fourth card is almost non-existant because of the performance issues at 4-way. (checked a review of 780ti & 780 in 1,2,3,4-way setup, the 4-way only just crawled above the 3-way in any game they benchmarked).