To begin understanding what is going on during your Mac computer’s “sleep” process, you should know the three different kinds of “sleep” modes in Mac history. “Sleep” is the default mode for Mac desktop. During this process, the RAM remains on. Because nothing is copied to the hard drive, there is nothing to retrieve upon restart, making it as quick as possible. It uses much less energy in the process still than just being on. If you simply leave your MacBook unattended, for instance, this is the state it will go in. During “Hibernation” contents of RAM memory are copied to the hard drive before sleep and the RAM shuts off. This way, when the computer is started again, it must be reloaded completely. This used to be the default in older models (pre-2005). Finally, during “Safe Sleep”, a mixture of sleep and hibernation, the RAM contents are written to the hard drive as a safeguard, yet the RAM remains powered-on. When a computer is re-opened, the contents are all ready and loaded for the user. Since 2005, this has become the default for all Mac laptops.
Despite the differences in the above sleep mode states, the following still occurs to every Mac computer:
- The processor setting is put into low-power state.
- Video output stops and any currently-connected external display will lose connection.
- Apple hard disks power down and some third-party SSDs may power down as well.
For Mac laptops, the following also occurs during any sleep mode:
- The Ethernet port turns off,
- Expansion card slots turn off
- The built-in modem, if present, turns off
- AirPort functions, if present, turn off
- The optical media drive, if present, spins down
- Audio input and output are disabled
- Keyboard illumination (on applicable devices) shuts off
- Ethernet port is disabled on most devices. NOTE: You can change your system settings to WOL (Wake on Lan) signal, if you prefer.
- USB ports turn off and only respond to the power key on an external keyboard.
- Bluetooth is disabled. NOTE: This can be changed in your Bluetooth system preferences, in which you can actually choose to make bluetooth devices power on your computer.
You can check which state of sleep your Mac laptop is in by going to Applications/ Utilities and typing “pmset -g | grep hibernatemode” into the terminal prompt. Your computer will respond with either hibernatemode 0, 1, 3, or 25. “0” is normal sleep, 1 is hibernate mode, 3 means safe sleep (most likely your response if you have a Mac laptop newer than a 2005), and 25 hibernate mode for portable Mac devices newer than 2005.
You can also use, and we suggest using, Mac energy saver preferences from the Apple Menu, under preferences, to adjust helpful energy settings. Here you can choose a faster or more appropriate length of time for your computer to fall asleep on power or battery. It is also here that you can change other helpful power settings such as “Enabling Power Nap,” allowing your computer to back up during sleep, and “Wake for Wi-Fi access.”
If you’re worried about the security of your laptop during safe sleep, you should know that it is about as guarded as it would be while it’s awake. One difference is that usually during sleep, there is no access to the network. Your computer should remain invisible during this state.
Most Mac users with portable Macs newer than 2005, choose to leave their Mac always on, depending on closing the lid of their laptop or lock screen to put their device to sleep. This is a function that Mac was built for and this is why the settings for each sleep state, especially ones designed specifically for 2005 or newer devices were developed the way they were. Despite what state you preference is, it is always good to occasionally reboot your Mac. Typically it is best to do this when updating software. If you have any questions about the state of your Mac and power settings, feel free to call Mac Enthusiasts at (800)448-1892 or contact us online here.