Initial Processing of Group Policy
For computers, Group Policy is applied when the computer starts. For users, Group Policy is applied at log on. This initial processing of policy can also be referred to as a foreground policy application.
The foreground application of Group Policy can be synchronous or asynchronous. In synchronous mode, the computer does not complete the system start until computer policy is applied successfully, and the user logon process does not complete until user policy is applied successfully. In asynchronous mode, if there are no policy changes that require synchronous processing, the computer can complete the start sequence before the application of computer policy is complete, and the shell can be available to the user before the application of user policy is complete.
All policy processing must be completed within 60 minutes. There is no method to modify this time-out period.
For more information, see Logon Optimization.