3 560 tis at that resolution should be fine. If you had gotten the 2GB versions I think you would have been happier and able to run higher texture and shader settings.
I run 2 GTX275 896MB and they handle most everything I throw at them. Games like MWLL (Crysis mod), RO2, ArmA2, BC2, BF3 and Skyrim for example, I need to keep it on a normal/medium texture settings, but other than that I run things up to High and VeryHigh settings and its smooth >45fps. I had tried 2 560 ti 2GB, and the performance increase was not worth nearly $600 (>$550 after tax) to me. About the only difference was I could max out the textures, although I was maxing out the 2GB in MWLL and ArmA2 and I was getting 100fps vs 60 in most games I play. And in heavily CPU bottle-necked games like MWLL and ArmA2 I was still down around 40fps at times, in the same place so I guess my >4ghz i7 isn't enough anymore.
Edited by frag85 - 8/30/12 at 4:47pm