Triple 760's maybe? Of course that takes a good PSU, and a motherboard that can support it, but unless you are spending a TON of money, that's most likely your best bet on a *reasonable* budget. Triple 660's beat 2 680's, so 760's would just be gravy. Figure 780 dollars for 3 x 760's, another 100+ for a PSU, and probably 140ish for a motherboard to support it.