Generally, by default Group Policy gets updated in the background every 90 minutes, after a change is recorded in the active object.
Even when you Change Group Policy Refresh Interval and set it at 0 minutes, the computer tries to update Group Policy every 7 seconds.
So eventually there exists the possibility of a decrease in the speed of the computer, since a Group Policy refresh in the background will affect system speed.
Normally, User Group Policy is refreshed at logon and Computer Group Policy is refreshed at machine reboot.
This tutorial will show you how to use the gpupdate command to force an update and refresh of either or both the Computer or User Group Policy settings to be applied instantly in XP, Vista, and Windows 7, and Windows 8.
There are some Group Policy settings that need exclusive access to the computer or user environment.
The most prominent ones are Software Installation and Folder Redirection.
Depending on which OS you are running, the command to refresh group policy is different.