FPS much lower after installing another game

so I bought Beamng around 2021 when I got a new pc and pbr came out, and it ran 70-100 fps average, and later I installed gta IV and now it runs at 30 fps most of the time. btw I have tried deleting gta, safe mode and still nothing. and I bought gta on steam so it can't be a virus

 

it crashes when I press submit information

 

i had the same problem and for me the problem was in the GeForce Experience app, if you have that app too then go to settings and find ''battery boost''. it automatically set a 30fps limit for me out of nowhere

 

that fixed it, thank you so much!