Macs that use Power Nap

The MacBook Air (Mid 2011 and 2012) and MacBook Pro (Retina, Mid 2012) running Mountain Lion can use Power Nap.

An SMC update is required to gain all the functionality of Power Nap.  Here is a list of the supported Macs and the SMC update that is required to support PowerNap:

When your compatible Mac goes to sleep in Mountain Lion, Power Nap still gets things done silently

• Mail. Receive new messages.
• Contacts. Your Contacts update with any changes you may have made on another device.
• Calendar. Receive new invitations and calendar updates.
• Reminders. Reminders updates with any changes you may have made on another device.
• Notes. Notes updates with any changes you may have made on another device.
• Documents in your iCloud account. iCloud pushes any edits you made to a document to your Mac notebook.
• Photo Stream. Your Photo Stream updates with new photos from your iPhone, iPad, or iPod touch.
• Mac App Store updates. Your Mac notebook can download updates from the Mac App Store.
• Time Machine backup. Your Mac notebook can back up while it sleeps.
• Find My Mac. Locate a lost Mac notebook even when it’s sleeping.
• VPN on demand. Corporate email updates securely.
• Configuration profile. Macs in managed environments can receive configuration profile updates.

Power Nap does more when your Mac is plugged in to an AC outlet

When your portable Mac is connected to a power source, it also downloads software updates, makes backups with Time Machine, performs Spotlight indexing, and it can continue Mac App Store downloads.  It also updates Help Center.

Silence

When Power Nap is doing its job, the system sounds are silent and no lights or fans come on.  When your Mac wakes up, it’s good to go.

Note: If you use the Play Sound or Send Message feature of Find My Mac, Power Nap does not make a sound.
Turning Power Nap on or off

Power Nap can be turned on or off in the Energy Saver pane of System Preferences.

It is enabled by default on supported computers when connected to AC power.

Power Nap is off by default when running on battery power. To enable it when running on battery, open the Energy Saver System Preference, click the Battery tab, and then click on the checkbox for Enable Power Nap while on battery power.

Power Nap won’t completely drain your battery

When your battery has 30 percent or less charge, Power Nap operations will be suspended until you connect a power adapter.  Power Nap communicates and transfers data for a only a few minutes per Power Nap cycle when running on battery.  When connected to a power adapter, communications and data transfers are continuous.

Applications and features that are configured use Power Nap

Mail, Contacts, Calendar, Reminders, Notes, Photo Stream, Find My Mac, Time Machine, Spotlight, the Mac App Store, Software Updates, Help Center and Documents in the iCloud are already Power Nap-aware.  You don’t need to do anything to configure them to be used with Power Nap.

How often does Power Nap check for updates?

• Mail, Contacts, Calendar, Reminders, Notes, Photo Stream, Find My Mac, and iCloud Documents are checked every hour.
• Time Machine backups are attempted hourly until a successful backup has been completed.
• Software Updates are checked daily.
• Mac App Store downloads are checked once a week.

Increasing battery life

Disconnect any USB, Thunderbolt, or Firewire devices that may draw power while the system is using Power Nap.  For more information about increasing battery life, see this website.

About Virtual Private Network connections and Power Nap

VPN connections that use a certificate to authenticate are supported, but not VPN connections that require entering a password.

Additional Information

When Power Nap is enabled, you computer may be warm to the touch even if it is sleeping. Power Nap operations will be suspended if your computer exceeds a predefined temperature; your computer will not overheat when using PowerNap.