Screensavers Considered Harmful

originally posted: November 12, 2008
last updated: November 12, 2008

Once upon a time, when computer displays were all crummy CRT's, there were problems with images getting "burned" into the display if they were left up too long. So screensaver programs were invented to keep the contents of the display changing when the computer is idle.

No modern computer displays still have significant burn-in problems, so the need for screensavers is almost completely gone. Unless your computer is more than 15 yers old, your screensavers no longer does anything at all to save your screen. But people kind of got used to them, and they look pretty, so many computers still have them.

From an energy point of view, screensavers are all bad. First many of them generate quite elaborate displays that require a lot of computation to generate. Most modern computers consume more energy when they are computing harder, so this is a loss. Furthermore, most computers have the ability to put their screen into a powersaving mode or turn it off entirely when the computer has been idle for a while. This is a much better alternative that can save a significant amount of energy.

In fact, powering down the display when it is not in use is also likely to lengthen the lifetime of the display. So if you really want to save your screen, this is a much better alternative.

I can think of only a few cases where a screensaver might actually be a good idea:

1. Productive screensavers. There are organizations like World Community Grid and Seti@Home which put your computer to work doing useful research whenever you aren't using it yourself. On some kinds of computers these tools install as screensavers - programs that run only when you aren't using the computer. They still spend energy, probably even more than typical screensavers because they run your CPU pretty hard, but they do it in a good cause.

2. Computers that should be off. One of the best methods of saving some of the energy used by a computer is to turn the computer off when you aren't using it. Putting the computer's display into a sleep mode may make you think the computer is off when it isn't. If you take the sight of a screensaver on a monitor as a signal saying "this computer should be turned off", then the screensaver may be doing some good. You could even set your screensaver to scroll the message "Save Energy! Turn Me Off!" across the screen.