Bad perfomance

[XDMakkara]

So i have a omen 25l prebuild and a rtx 3070 i7 11700 f 2.50 hz. 16gb ram. And ive had this computer a while and all was ok but out of nowhere a few weeks ago my computer just started performing so bad. Before i had like 400fps fortnite and 300 in cs go but now i have 100 fps in both games all low settings. My gpu usuage never goes like more than 20%. And my psu is 500w. What  can i do to fix this.  Ive upgraded my drivers my temps are ok and speeds are : Gpu core clock 1725z  mhz and memory 7200hz. My cpu is also like 4.5 ghz usually. I really dont know what to do, Can someone help.

[XDMakkara]

And i have like 200 fps i did a geekd3d benchmark and i got a good score so the problem is like my gpu is lazy when im playing games. WHen doing the benchmark i had 80% gpu usuage and good fps but when playing only 20% and 100 fps