Originally Posted by PostalTwinkie
Dual 760 Ti over a single 770 in terms of raw performance. Though with dual 1600P, good luck pushing frame rates of any decent level.
670 SLI does great at 1600p and i'm sure 760ti (if it matches the 670) will also be just fine. It should also be mentioned that with nvidia cards, you can't do surround with only 2 monitors, you can only use monitor spanning in 3d applications with 3 monitors. So with that being the case -- the primary display will be for gaming and the secondary display will be an accessory display. What you cannot do, as mentioned, is span the 3d game across two monitors in a surround resolution.
But, with the original question: 760ti SLI will kill it at 1600p, assuming that they match the 670 in performance.