install msi afterburner, this will also install RTSS.
You then configure OSD settings so in game you can see the following.
CPU usage
CPU clock speed
GPU usage
GPU clock speed
GPU power utilisation (if nvidia kepler or newer)
Framerate
Monitor these as you play on the screen and you can see if cpu or gpu max utilises.
An alternative which might be easier for you is just grab gpuz and have that running in the background (maybe also with logging enabled) and have it set to monitor whilst in background. That works on both amd/nvidia. GPUZ wont monitor cpu usage tho. But if you go the gpuz route, you can just leave task manager running in background to graph cpu usage.
All these are free tools.
Remember not all games are good at cpu multi core utilisation, so if you see one of e.g. four cores maxed out on the cpu that still probably means you cpu bottlenecked even if other 3 are idle.
Edited by Chrysalis (Sat 13-Aug-16 20:57:24)