When Windows 7 is configured with the following settings, the desktop may fail to update for several seconds after waking the monitor.
Task-bar set to auto-hide
Turn off the display power option is set to 1 minute
Put the computer to sleep power option is set to never
No open windows on the desktop
After letting the machine sit idle for 10 or more minutes, you may notice that the task-bar does not pop up when moving the mouse to the bottom of the screen, or the start menu does not appear when using the windows key. After approximately 30 seconds, Windows will return to normal operation.
The delay is caused by a large number of items being processed by the Graphical Processing Unit (GPU).