First off, ensure that a temporary glitch hasn't fueled the high CPU usage by the Vanguard user-mode service process. The easiest way to rule out this possibility is to close Valorant, turn off the Vanguard services, and restart them. To disable them, right-click the Windows Start button and open the Task Manager.
Valorant lagging and stuttering in your system may be due to a process called "Vanguard user-mode service," hogging more CPU resources than it should. Fortunately, there are a few ways to tackle the confusing problem.