if your trying to run at more than medium then thats your issue.
the game is a monster for requirements. to max it out you will need a titan, a 690, a 7990 or 2 680's
even 2 gtx 670's will struggle to get up to 60 fps.
crysis 3 does like high thread count cpu's but it doesnt care about speed as long as there over 2.6ghz.
so my guess is your running it at to high a setting that your card cant handle.
try running at medium with fxaa rather than smaa
It need not be a bottleneck. Lower the Resolution, and play the game on lowest, and see if the fps improves. If it does, it might just be that the game is not well optimized to use all your GPU Raw power.