Temporary freezing/ lagging while playing games

I have a Dell Latitude 3450 (16 GB ram version) which I often use for gaming but for a few weeks I am experiencing a sudden fps drop while playing games the fps drops to 1 or 2 for a few minutes then reverts back to normal this happens in every game I play. I ran a diagnostics test and nothing was wrong I already did everything possible from disabling startup apps to msconfig (literally everything Google could offer ) Any help would be appreciated. I don't what is at fault here drivers or hardware.