You have to do your own digging to first to determine if something is holding you back. Then you can ask for recommendations on how to solve it. Right now it's all guessing.
If your CPU is at 100% usage while you game, then you need to figure out why that is. Maybe it's normal. Maybe it's not.
If your GPU is at 100%, then maybe its simply maxed out. You can combat it by lowering your in-game graphic settings.
If your CPU temperature is at 100ºC, this is too high and the system might be lowering the clock speed to bring the temps down, affecting overall performance
If your GPU is sitting at 100ºC, then the graphic drivers are going to slow the GPU clock speed down to try and keep the card lower, and this will affect your game performance.
Mind you, 100ºC is an example. I only used it because most components would scream murder at that temperature. Throttling can happen at much lower temps, depending on the hardware.
Get this tool:
https://www.msi.com/page/afterburner
You will have to look up some guides on how to configure the on screen display. You Tube has lots of tutorials. Be aware that this is primarily an overclocking tool, so don't mess with settings if you don't know what you're doing.