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To Sleep or Not to Sleep...and Other Power States Explained

In this tech tip, you'll learn when to put your computer or laptop to sleep, and when it's better to shut down. We'll also cover hibernation on PCs.

Modern computers are equipped with several features that conserve power. Even desktop computers are programmed to blank the monitor, and spin down the hard drive and the cpu during periods of inactivity. But, how do you know what state to leave it in when you know you won't be using the computer for a while?

Sleep (Mac) or Standby (PC)

Sleep is a handy way to safely move a laptop computer from point A to point B, as it turns off the hard drive; this prevents potential damage to files. By all means, put your laptop to sleep as you travel from building to building on campus. There are, however, some times when it is better to simply shut off the computer, rather than putting it to sleep or standby.

  • Laptops still use some power when sleeping, so you don't want to put it to sleep if your battery charge is low, especially if you won't be plugging it in soon. If you do this, your computer may power down while sleeping and will require that you press the power button to wake it. If the battery was drained, you must plug in the laptop before it will wake.
  • Your computer needs to be restarted periodically to be refreshed and to perform some routine maintenance. It is best to simply shut down your computer if you are not going to be using it for 12 or more hours.
  • Wireless network connections sometimes do not refresh when you move from one network to another in sleep mode. It is better to shutdown your computer when traveling between networks, or restart when you arrive at a location with a different wireless network.

Hibernation: A deeper state of standby

Hibernation is another state that is available on Windows PCs. When a PC is put into hibernation mode, it actually shuts down and does not use any power. Before doing so, it saves all the current settings to a special file on the hard drive. That way, when you power the computer back up by pressing the power button, you will be returned more quickly to the desktop exactly as you left it.

For a more detailed explanation of power states on Windows PC's, see the "Information Week" Langa Letter at

To shut down or not to shut down

Back in the dark ages of computing, many tech support specialists advised that the computer never (or rarely) be shut down. They explained that this would save wear and tear on the hard drive and other computer components. That's less of a concern today. Shutting down the computer saves energy and allows the computer to be refreshed. Of course, you should avoid turning your computer off and on frequently, but it's fine to shut down your computer daily. If you do leave it on all the time, it's a good idea to turn it off at least once a week to let the computer reset itself.

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