Screensavers

Monitors running screensavers consume the same amount of power as when running normally, which can be anywhere from a few watts for small LCD monitors to several hundred for large plasma displays. Most modern computers can be set to switch the monitor into a lower power mode. A power saving mode for monitors is usually part of the power management options supported in most modern operating systems, though it must also be supported by the computer hardware and monitor itself.

Additionally, using screensavers with a flat panel or LCD screen instead of powering down the screen can actually reduce the lifetime of the display, since the fluorescent backlight remains lit and ages faster than it would if the screen was turned off completely. As fluorescent tubes age they grow progressively dimmer. A typical LCD screen loses about 50% of its brightness during a normal product lifetime. (In most cases, the tube is an integral part of the LCD and the entire assembly needs to be changed out)

Thus the term "screen saver" is somewhat a misnomer—the best way to save the screen (and also save electricity) would simply be to have the computer turn off the monitor.

Notice also that screensavers as well may utilize a significant amount of CPU time. On a busy server this might be a problem.

An early screensaver for the Macintosh platform, and later PC/Windows, After Dark, prominently featured whimsical designs such as flying toasters. Perhaps in response to the workplace environment in which they are often viewed, many screensavers continue this legacy of whimsy by populating the idle monitor with animals or fish, games, and visual expressions of mathematics equations such as fractals.

The screensaver is also an outlet for the work of creative computer programmers. The Unix-based screensaver XScreenSaver collects the display effects of other Unix screensavers, which are termed "display hacks" in the jargon file tradition of US computer science academics. It also collects forms of computer graphics effects called demo effects, originally included in demos created by the demo scene.