I have set the display to turn off after 3 minutes of inactivity on both, my (Windows 8) PC & (OS X 10.8.2) Mac Mini 2011.
Both share the same Acer LED.
So, obviously the GPU cuts the video signal after 3 minutes of idle time. But, does the GPU go to a low-power state when the signal goes down? Or does it still consume the same amount of power which it does when it's idling on the desktop?
If the difference in power consumption is negligible, then I'd just cycle the monitor's input instead of going through a two-step process while moving from one computer to another (which includes pressing keys on the keyboard/moving the mouse, and then cycling the monitor)