Question FPS low in some games with good GPU

[tomaslogii]

I recently got a new graphics card, a 3060 ti. I also had to get a new PSU. On some games i get the FPS i should get but then there are the games that my fps is the same on my old GTX 1660. I have a i5 9400f, i don't know if the CPU is holding me back or not. When i play for example CS:GO i get around 240-330 FPS on low settings but on Fortnite or PUBG i get 100-180 FPS on low settings. When i was playing Tom Clancy's Rainbow Six Siege my CPU usage was 100% and not moving whilst my GPU usage was running at 7% and lower. Does anyone know how to fix this?

 

[rgd1101]

check cpu temp?
new build or upgrade from something else?