The game lag/stutter for 2 secs after every 5 secs

My game is experiencing a very regular freezing. It freezes in every 5 seconds. Not stuck. The mouse can still move, and after two seconds it will return to normal, but I have to experience this stutter every 5 seconds, which affects the game experience very much. The problem doesn’t appear while playing other games.
Internet is fine, CPU and Graphics are fine. Does anybody know how to solve this problem?