Question Weird Minecraft GPU Usage and FPS bug

[Neetus]

For some reason my Minecraft is only using 20% of my GPU, and when my game is in idle or if I change windows to a different one, my GPU randomly goes up to 90% and the FPS bumps up from 90 to 500. I am extremely confused as usually id expect it to be the opposite way, for context I used to run minecraft at 500 fps with high GPU usage and I honestly dont know what happened for this sudden change to take place.

 

[rgd1101]

full system spec? include brand and model of the psu
what the cpu usage when the gpu usage is low and when it is high