on my cpu, clocked at 4ghz, cpu usage is between 85-95% averaged across 4 cores. It is able to keep fairly smooth performance through the game (60fps with vsync on most of the time), although im sure the finished game and more driver tuning will iron out the few stutters and things encountered.
http://www.bf4blog.com/battlefield-4-beta-gpu-cpu-benchmarks/
heres a good bench, the 8350or 2600k looks like its utilized 67% on average so 8 threads aren't fully utilized by the game. the 6300 is more or less maxed out on all cores though. the 3970x show 7 threads used out of a possible 12, but shows a significant performance increase over the other cpu's, so the game is somewhat cpu bound, at least the beta is