PC deep sleep with Vista

Vista may do a better job at conserving energy when you set your PC to hibernate.

In Windows XP, when you set your PC to hibernate, some applications and hardware devices could override the hibernation command and continue to run (e.g virus scan or DVD burners). However, in Windows Vista, your PC will no longer allow applications and hardware to override your hibernate and "stay up late." They will be warned when the computer is about to catch some zzzs, and will have a second to save their progress. So, when you tell a Vista PC to go to bed, it actually listens.