I had a pair of 8600GT cards that were SLI capable... but they didn't quite do what I wanted anyways. If you wanted a decent SLI setup, you could spend ~$200 on a pair of 9800GTs which would give you really good performance in a lot of newer games at medium-high resolution. The 9800GTX was a little disappointing to me, not really anything special in my opinion. Never tried to SLI a pair though... probably just get a GTX 260.