Install MSI afterburner and set up on screen display of the CPU and GPU usage. This will allow you to see how much of your CPU and GPU is being used while in-game.
If either your CPU or GPU is being used to 100 percent then there is nothing much you can do about it as that component is a bottleneck and is already being used to it's maximum.
But if your GPU or CPU both are under like 70 percent usage, then your game might not be using hardware to it's maximum potential.
While you are at it, you can also check the temperature of your GPU using MSI afterburner when in game to check if high temperature is the issue. When the CPU/GPU hits the temperature cap, then it scales back down which degrades performance completely.
Here are guides on how to use on screen display features of MSI afterburner :
1. http://www.gameplayinside.com/optimize/how-to-check-your-frame-rate-and-gpu-usage-in-any-game/
2.
http://www.zombiemodding.com/index.php?topic=12554.0
Set it up, check your CPU usage, GPU usage, and temperatures on the same and report back the results you are getting. Your PC is most likely GPU bottlenecked, for which sadly not much can be done.[/quotems
The Cpu is about 85%
and gpu is about 70% and the temp is about 40 Celsius