Is there anyone using 2560x1600 (30" Monitor) with GTX 680?

I recently did an experiment using a 30" monitor: going from GTX 570 to GTX 580 gains 6-7 FPS. I wonder if going to the GTX 680 will benefit since going to the GTX 580 from GTX 570 demonstrated GPU limit for large resolution. I had a GTX 570 SLI setup as well and that did nothing to the FPS: same as GTX non-SLI. If someone has this setup and had moved up to GTX 680 please let me know.

Thanks

(My PC spec is in the link)