Guys I'm currently at a dilemma and have been since the release of the GTX 680.
I am currently running SLI GTX 580 and I'm thinking of selling them whilst they are worth something and buying a GTX 680 in place of it (and possibly SLI afew months later down the line, depending on the performance of the single card).
I play my games : 1920 x 1200 which some say is overkill, well my problem is I can't stand playing my games less than 60fps. It feels sluggish, I notice it easily and I hate it. The most stressful game that I play is Battlefield 3 which I would like to max out at 60fps (I play with vsync on) but I play more MMORPG'S than anything which in that case the 580's are overkill .
I've tried to be deciding myself all week, but what do you guys think? I already know that SLI 580's run faster than one 680 but I'm not bothered in taking a hit aslong as I can still game with 60fps.
Honestly, you will not be seeing a massive increase over switching to a single 680. in various reviews, the 680 typically did under the 590 GTX/6990 Radeon. I am actually looking to get a 2nd 580 GTX, for SLI, just because it will be about 200-300 dollars cheaper then me buying a new 680.
The scaling on a 580 may not be 100% in SLI, but the performance gain to just going to a 680 won't be enough to justify the cost IMO. your system is already solid, I suggest keep it as it.