FPS drops from 120 to sub 30 randomly and then comes back to 120

Its most prevalent in Team deathmatch but for some reason I start every game with a regular 120 fps and it suddenly goes to 30 or below fps. I am on lowest possible settings and have tried lower resolutions with the same result. It didn't happen before and I haven't installed any heavy programs in my device previously. I have 16gb RAM, i7 core and nvidia rtx 2060 gpu