Screen Saver timeout
User Configuration\Administrative Templates\Control Panel\Display
Specifies how much user idle time must elapse before the screen saver is launched.
When configured, this idle time can be set from a minimum of 1 second to a maximum of 86400 seconds, or 24 hours. If set to zero, the screen saver will not launch.
This policy setting has no effect under any of the following circumstances:
If the policy setting is disabled or not configured.
If the wait time is set to zero.
If the Activate Screen Saver policy setting is enabled.
If neither the Screen saver executable name policy setting nor the Screen Saver tab of Display in Control Panel on the client computer specifies a valid, existing screensaver program on the client.
When not configured, whatever wait time is set on the client through the Screen Saver tab of Display is used. The default is 15 minutes.