An energy-saving PC. All modern computers, printers and monitors are greener than their predecessors. After a certain period of time, they switch into low-voltage modes or turn off, although these settings are often user definable. Laser printers especially waste a lot of energy when not in use, because of their heat-induced fusing mechanism.Contemporary CPUs often run at variable clock rates and can idle at lower speeds to save electricity. When required, they ramp up to full power. See green.