Overall
SLI and crossfire testing is always surprising to me, its always interesting to see what you can get when you pair up a couple lower end cards. In this case we ended up with performance up and over the GTX 680 with two GTX 650 Ti Boosts. The lowest price I could find on a GTX 680 currently is $439.99 and the lowest price on a GTX 650 Ti Boost as of this writing is $169.99. That puts the SLI at 339.98 a whopping $100 less than what it would cost you to get a GTX 680. Of course going with SLI now means you won’t have room to upgrade later, but if you can’t afford a GTX 680 right now you could get a GTX 650 Ti Boost now and pick up a second one when you have the money to get performance over the GTX 680.
There are a couple things to consider with going with this setup over a more powerful video card. First, if you like to play games when they first launch you aren’t going to see the best performance until SLI drivers are tuned and in some cases there might not be SLI at all for a few weeks. Going with two cards means you will need a larger PC, those of you who are interested in small form factor builds should still be looking at a single card. As someone who has run almost every variation of crossfire and SLI day to day you will also most likely run into small quirks here and there with the drivers and micro stuttering as well.
Personally I would still be considering a pair of GTX 650 Ti Boosts for a build. Not only are you going to get a better price, but you are also going to get a performance increase over the GTX 680 or HD 7970 that will make it worth your while.