Well, I'm running 3 TFTs with 6016x1200 full screen on a Sapphire Radeon HD7950 OCed at 1050/1500 with 3 GB VRAM.
Default P3Dv2, 4xMSAA (RadeonPro enhancing Adaptive) and 16xAF, Tessellation off, shadows off, Mesh 5m, Water High, all other sliders maxed out (and as usual: FPS unlimited). Looks great!
I'm hitting the 3 GB VRAM Limit (considering overhead) once I choose the default "Thunderstorm" weather theme. FPS immediately drop and the RAM DIMMs get hot..
So, I think it's not all about GPU core power but VRAM might be also an issue here. I3570k OCed at 4,4 GHz with tessellation and shadows off might be capable of >30 fps but my RAM with VRAM full might be not. Will continue testing..
Cheers,
ayam47