Considering GW2 can be maxed out on a
$230 HD7870, gaining more performance in that game is meaningless to get NV back into the lead.
NV needs to improve performance in all of these first:
- Anno 2070
- Bulletstorm
- Serious Sam 3
- Batman AC + 8xMSAA
- Skyrim + Mods + 8xMSAA
- Arma II Operations / Day-Z mod
- Sniper Elite V2
- Dirt Showdown
- Sleeping Dogs
- Metro 2033
- Crysis 1 / Warhead
- Alan Wake
- Risen 2
That's a long list where 680 is slower. Until NV addresses those games or some newer games that take advantage of Kepler architecture come out (BL2, Medal of Honor), NV won't reclaim the single-GPU performance crown.