A new Apple Knowledge Base article says Mac computers manufactured in 2013 or later enter standby after three hours of “regular” sleep. Earlier computers activate after just over an hour of “regular” sleep.
Macs that can use standby mode include:
MacBook Pro (Retina, 13-inch, Late 2012) and later
MacBook Pro (Retina, 15-inch, Early 2013) and later
MacBook Pro (Retina, Mid 2012)
MacBook Air (Mid 2010) and later
SSD and Fusion drive versions of Mac mini (Late 2012) and later
SSD and Fusion drive versions of iMac (Late 2012) and later
To enter standby, the computer must:
Be running on battery power (if it is a Mac notebook computer).
Have no USB devices attached.
Have no Thunderbolt devices attached.
Have no SD card inserted.
Have no external display attached.
Apple says that a computer with a fully charged battery can remain in standby for up to thirty days without being plugged in to an AC power source. The state of the computer is saved to the flash storage (SSD), then the power to the hardware subsystems turns off to increase the length of the standby. For example, RAM memory and the USB bus are powered off during the standby.
To exit standby, do any one of the following:
Press a key.
Open the lid.
Click the trackpad.
When the computer exits standby, the state of the system image stored on the flash storage is used to restore the system to its pre-standby state. The computer returns to full operation within a few seconds.
If you leave a Mac notebook computer in standby long enough for the battery to deplete fully, the computer will shut down. You can recover your computer to its pre-standby state and any unsaved work should not be lost. To exit standby at this point, attach the computer to an AC power source and press the Power button.
Apple also notes that if you find that your Mac computer seems to be taking longer then usual to start up or seems slow to wake from sleep or standby, make sure the startup disk is set correctly in the Startup Disk preferences:
Choose System Preferences from the Apple menu.
Choose Startup Disk from the View menu.
Make sure your internal drive is selected.
For more information, visit: