OS X Mountain Lion: Energy Saver preferences

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Energy Saver preferences

Use Energy Saver preferences to set options that control your computer’s energy use. If you have a portable computer, these options also help you extend your battery’s life.

For example, you can set your computer, or just your display, to sleep automatically when it’s inactive for a period of time. If your computer is in the middle of a task that you want to finish, you should set only the display to sleep.


Your computer meets the ENERGY STAR program requirements for energy efficiency. Reducing energy consumption saves money and helps conserve valuable resources. For more information about ENERGY STAR, see:


The options available depend on the computer you’re using. These options aren’t available on all computers.

Option Description


Select an option to adjust the tradeoff between battery life and graphics performance. You need to log out and then log in again for the change to take effect.

Automatic graphics switching

Select to switch between graphics modes for better battery life. If this option is deselected, your computer always uses high-performance graphics and your battery life may be shorter.

Battery, Power Adapter, and UPS

Click Battery, Power Adapter, or UPS, and then select energy-saving options for that power source. Your computer will use those options when it’s getting power from that source.

You see the Battery button only if you have a portable computer. You see the UPS button only if your computer is connected to an uninterruptible power source.

Put the hard disk(s) to sleep when possible

Select this option to put the computer’s hard disk to sleep whenever it’s inactive.

Wake for network access

Select this option if you want other users to be able to access your computer’s shared resources, such as shared printers or iTunes playlists, even when your computer is in sleep mode.

Slightly dim the display when using this power source

Select this option to reduce the brightness of the display while the computer is using the battery.

Automatically reduce brightness before display goes to sleep

Select this option to always reduce the brightness of the display before the display goes to sleep.

Start up automatically after a power failure

Select this option to always start up your computer after a power interruption.

Restart automatically if the computer “freezes”

Select this option to restart your computer after it stops responding or has a kernel panic.

Show battery status in the menu bar

Select this option to show your battery’s charge level in the menu bar. If your computer is plugged into an electrical outlet, the icon indicates whether the battery is charging or is fully charged.


Click this button to set a daily schedule for putting your computer to sleep or turning it off and on.

Published Date: Sep 4, 2015