All about Energy Saver idle and sleep modes in Mac OSX
Energy Saver idle and sleep modes in Mac OSX
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We all know that energy is important and it’s our duty to preserve it. Apple knows it very well. That’s why your Mac comes with various energy saver modes. So that when your Mac is not being used, there is minimum consumption of energy using any of these energy-minimising modes. These modes are: Energy Saver sleep mode and Energy Saver idle mode. Let’s learn more about them in detail:

Energy Saver idle mode

Energy Saver idle mode is designed to fit in the situation when your Mac is left unattended for some time. You can change the Energy Saver idle mode settings from ‘Energy Saver preferences’.

The ‘Energy saver’ preferences come with variety of options, which you can set as per your choice and preferences.

How to put your Mac in idle mode?

You don’t need to apply any special trick to put your Mac in idle mode, as the mode is already active by default. Just leave your Mac idle for some time, and the mode will automatically come into play.

What happens when the Mac is in idle mode?

If you set the “Display sleep” slider lower than the “Computer sleep” slider:

  • The display will sleep if you leave it unattended for some time
  • If it remains idle longer, it’ll go into full sleep mode after display sleep

However you can’t do the reverse i.e. you can’t set the “Computer sleep” slider lower than the “Display Sleep” slider, because computer sleep also includes display sleep.

Gentle reminder:

On some earlier portable Macs, the above window displays a Graphics choice of “Better battery life” or “Higher performance”.

Energy Saver sleep Mode

Energy Saver sleep mode refers to the mode, which becomes active when you put your Mac to sleep.

How to put your Mac to sleep?

Normally leaving your Mac idle for some time will put it in sleep mode. However you can also put it to sleep immediately. You just need to apply any of these methods:

  • Choose Sleep from the Apple menu
  • Click Sleep after pressing the power key
  • Close the lid of your Mac

What happens when the Mac goes to sleep?

On all Macs:

  • The microprocessor goes into a low-power mode
  • Video output is turned off, and a connected display may turn off or may enter its idle state
  • Apple-supplied hard disks spin down; third party hard disks may or may not

On portable Macs:

  • The Ethernet port turns off, if applicable
  • Expansion card slots are turned off
  • The built-in modem, if present, turns off
  • An AirPort card, if present, turns off
  • The USB ports only responds to the power key on an external keyboard
  • The optical media drive, if present, spins down
  • Audio input and output turns off
  • Keyboard backlit, if available, turns off


As compared to the idle mode, your Mac uses considerably less power in sleep mode. The computer will continue to power RAM in sleep mode, so whatever was in RAM when your Mac went to sleep will still be there when it awakes again. So it’s much wise to put your Mac in sleep mode.


Both modes have their own significant advantages. One lets you choose best from a variety of options, while other use considerably less amount of power and that even without any need to tweak some settings. You can choose any one of the above!