OS X Mountain Lion: Change Power Nap settings
If your Mac supports it, Power Nap is on by default when your Mac is plugged into a power adapter.
You can change the default setting and decide if Power Nap is turned on based on whether your computer is plugged into a power adapter or using battery power. You can also turn Power Nap off completely. To change Power Nap settings, use the Energy Saver pane of System Preferences.
- Choose Apple menu > System Preferences, and then click Energy Saver.
- Click Battery or Power Adapter, depending on which setting you want to change.
- Select or deselect “Enable Power Nap while on battery power” or “Enable Power Nap while plugged into a power adapter.”
If you have a compatible computer and you don’t see the Power Nap settings, you may need to perform a firmware update. To check for firmware updates, choose Apple menu > Software Update.