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Green IT: Configuring Power Settings in OS X

Follow the instructions below to configure power settings in OS X Snow Leopard 10.6, OS X Lion 10.7, and OS X Mountain Lion 10.8.

Locating Power Management Settings

  1. Click on the Apple symbol (Apple Menu) in the upper left of your screen
    • Go to "System Preferences"
    • Click "Show All" (if necessary)
  2. Select "Energy Saver" from the "Hardware" row

Customizing Your Settings

  • Use the sliders to customize:
    • Computer Sleep
    • Display Sleep
  • Additionally, you can utilize the check boxes to allow the hard disk to sleep, enable wake on network access, reduce brightness, and restart automatically after a power failure.
  • Using the "Schedule..." button, you can automatically start up and shut down your computer on a schedule.
  • Portable computer users can specify an alternative power profile that will take effect when the Mac is running on battery power.

EPA Recommendations

EPA recommends setting computers to enter system standby or hibernate after 15 to 60 minutes of inactivity. To save even more, set monitors (displays) to enter sleep mode after 5 to 20 minutes of inactivity. The lower the setting, the more energy you save. The "Put the hard disk(s) to sleep when possible" setting does not save much power, and can be ignored.

Penn Recommendations

End users should always consult with their Local Support Provider or ITA before adjusting the Power Settings on their computer. Some of the more energy efficient options (i.e., Sleeping) may impede management tasks (such as patches or system updates).

Display sleep should be enabled with a relatively short interval (5-10 minutes) in lieu of utilizing a screen saver. Not only will this setting drastically reduce energy usage (as much as 78 watts can be saved), but it will significantly prolong the life of many monitors by reducing the amount of time the backlight is lit.

Special information for Remote Desktop Users

Computer users requiring off-hours remote access to their desktops (via Screen Sharing, for instance) should utilize display power management features only. Remote access technologies may not be able to remotely "wake" computers from system sleep or schedule power down.

Troubleshooting OS X Sleep Issues

Please see Apple's Help Document: "If your Mac computer will not go to sleep or stay in sleep" for some key troubleshooting steps.


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