About graphic card and crysis 3

You can max out crysis 3 with acceptable fps 45+fps on a gtx670 card or a overclocked hd7950 or a hd 7970. Using SLI or crossfire won't provide a significant boost on gaming. Also there are many problems tied to SLI and crossfire. Haven't tried crysis 3 beta myself but will surely get crysis 3 when it comes out and then only I can post the fps.
Note. Currently newegg is offering free crysis 3 and bio shock infinite with AMD hd series cards.

The performance people are currently getting in the game will not be the same as what they will get when the title is launched. Because it will be better optimized by then and our drivers will receive an update. If Crysis 2 is any indication (in Ultra MSAAx4 with the HD texture pack), a GTX 670 or HD 7950 boost is the bare minimum to have. With those GPUs, you get on average 45fps at 1080p. We can safely assume that Crysis 3, despite being based on the same game engine, will be even more demanding, due to the various technical improvements that have been made.

a single gtx 670 or a radeon 7950 would suffice. Driver optimisations will improve the performance further. 40+ fps is achievable with either of the cards. NO need for cf/sli.

Radeon 7950 is only capable if heavy overclocked.

GTX 670 can just keep up with 45 FPS in average. I made benchmarks and a video of the performance.

http://www.youtube.com/watch?v=_J1_zPKa-AU

My 6870 (HIS ICEQ Edition) overclocked to 950/1100 runs fine at ALL medium. I get around 40-70 fps. Also...at 1080p the game looks great. In fact I didn't see such a huge difference that was worth the frame rate hit on high or possibly ultra. Keep in mind I can run higher graphics but it's not wise for MP play but it can be upped for SP play. I'm hearing absolutely horrible issues with the new AMD drivers though so I'm sticking with the 12.1 Cats for now until I hear no more BSODs or worse...failing to boot nightmares. Make sure to take off Vsync in Crysis 3, for whatever reason, it KILLS the frame rates and creates mouse lag.