The Energy Saver program helps you and your Mac in a number of ways. By blacking out the screen after a period of inactivity, it prolongs the life of your monitor. By putting the Mac to sleep half an hour after you’ve stopped using it, Energy Saver cuts down on electricity costs and pollution. And on a laptop, Energy Saver extends the length of the battery charge by controlling the activity of the hard drive and screen.
When you first open Energy Saver, you’re shown a pair of sliders, one of which starts out dimmed.
If you don’t see the sliders, click the Show Details button. (You’re probably using a laptop—and on laptops, the sliders are normally hidden.)
The top slider controls when the Mac will automatically go to sleep—anywhere from one minute after your last activity to Never. (Activity can be mouse movement, keyboard action, or Internet data transfer; Energy Saver never turns off your Mac in the middle of a download.)
At that time, the screen goes dark, the hard drive stops spinning, and your processor chip slows to a crawl. Your Mac is now in sleep mode, using only a fraction of its usual electricity consumption. To wake it up when you return to your desk, press any key; everything you were working on, including open programs and documents, is still onscreen, exactly as it was. (To turn off this automatic sleep feature entirely, drag the slider to Never.)
For more control over the sleeping process, activate the second slider by turning on “Use separate ...