Then I suggest the GTX 650ti Boost. These cards are damn quick! I recently had a 670 crap out on me and it got to the point where I could only play a game for about 10 munites before it would restart my entire computer. On a budget, I decided against getting another 670 and decided to shop around. I ran across the 650ti Bosst and thought "Wonder how they'd compare to the 670 in SLI". I picked them up and was immediately blown away. For a savings, I got way more power than I though I would.
If anyone is interested in building a nice gaming rig on a budget, I highly recommend these. Cheaper than a single 670 and out-performs it.
Now, the question will come up about some games and their support for an SLI setup. Most games nowadays will either come straight out capable of supporting it, while other will eventually have an update to support it. With the 650ti Boost cards, I see very little micro-stutter as well.
DirectX 11 synthetic performance
Heaven 4.0 – FPS: higher is better
GTX 650 Ti Boost SLI – 27.4 (14.6)
HD 7790 CrossFireX – 18.3 (6.7)
GTX 670 overclocked – 21.6 (14.7)
Bioshock Infinite - FPS: higher is better
GTX 650 Ti Boost SLI – 48 (10)
HD 7790 CrossFireX – 32 (5)
GTX 670 overclocked – 44 (17)
GTX 650 Ti Boost SLI – 35 (23)
HD 7790 CrossFireX – 17 (5)
GTX 670 overclocked – 29 (18)