If your GPU is at 100% utilization but CPU is only at ~50%, you're probably GPU-bound on the game you're playing. (Your GPU is already working at max capacity so your CPU can't be used fully.)
Have you tried comparing your results to other similarly spec-ed systems (ideally the same model-- some reviews have benchmark results that might be able to help)? This can give you a general idea of if you're in the right range or not for your FPS.
Also, a few questions for you, similar to what I sent out to another user in this thread:
Zisan, to clarify--your CPU and GPU are only running at 50% utilization?
A couple questions for you: