Navigate to Settings and click the Components tab which should be the second one.Open the Avast user interface by clicking its icon at the system tray or by locating it in your Start menu entry.Anything that does its job in real-time can be heavy on the processor so it’s sometimes the best to simply uninstall this component. It seems that the component most responsible for this problem is Avast Cleanup which acts in real-time in order to free some resources allocated by other background apps. How to Stop Avast Service from High CPU Usage? 1.