[SOLVED] Issues Cpu i5 8400 @2.80ghz Help appreciated

[EatYOuRNuGGeT]

Hey,
i've noticed that my Cpu almost always runs at 100% when i play modern games. the Fps i get can vary from day to day. some days i play a game and get 130fps other days i play that exact game and i get 60/80fps. im pretty sure this is a CPU issue as taskmanager says it runs at 100% the moment i start a game. my pc specs are I5 8400 @2.80 GTX 1070 and a H310 Motherboard. its a prebuild pc. Suggestions on how to solve this would be appreciated

 

[rgd1101]

cpu temp during the game?
make and model of the psu?

 

[aocon62]

Memory is a large play in poor performance. I have an 8400, and it runs well as soon as i bought a dual kit of 3000 mhz ram. But variable performance does sound like either weak power draw or poor cooling.