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To Sleep, Part Two

So, can you turn off Safe Sleep? Or switch to true Hibernation? Yes and yes, but you must use the Terminal command line, because those options aren’t available in the Energy Saver preference pane. It should also go without saying that these "tricks" aren’t supported by Apple, so execute at your own risk. That said, if you want to switch off Safe Sleep altogether, then fire up Terminal and enter the following command. When running this command (and the ones that follow) you’ll need to enter an administrator-level password, and then reboot the computer:

sudo pmset -a hibernatemode 0

If you want to use Hibernate mode instead, enter the command:

sudo pmset -a hibernatemode 1

Now when it's put to sleep, the computer copies the contents of RAM to the hard drive just as in Safe Sleep, but instead powers down the RAM afterwards to further conserve power. Obviously, the contents of RAM are lost when this is done. (Remember, Safe Sleep leaves the RAM powered and only uses the hard disk backup of the RAM contents if the computer happens to lose power completely). When you put your notebook to sleep in this way, notice that the sleep status light glows while the data from RAM is being backed up, just as with Safe Sleep, but when it’s done, the light goes out altogether, as if the machine was switched off. Pressing the keyboard or opening up the display won’t awaken the computer when it is hibernating; to wake up a hibernating MacBook or MacBook Pro you need to press the Power key, just as if you were starting up the machine. A gray screen will appear while the machine restores the contents of memory, and you’ll see a progress bar towards the bottom of the display. This will give you some idea of how long the process will take; typically 20-30 seconds:

If neither of these options is appealing, you can also revert to Safe Sleep mode by entering the following:

sudo pmset -a hibernatemode 3
Figure 5

Figure 5 If your Mac needs to recover the RAM contents from the hard drive to memory after being awakened, you’ll see a gray screen and a progress bar until the memory contents are fully restored.

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