MacBook Safe Sleep

We had a bit of a discussion last night at Xcake about the MacBook sleep time. Since switching to Intel chips MacBooks use what is called Safe Sleep, which suspends your RAM to Hard Disk when you shut the lid. The standard habit of a Mac user since PowerPC days was to shut the lid and throw in your bag, however on safe sleep it can take between 25 and 45 seconds to actually sleep, during that time the disk is likely still spinning.


There is another way. By disabling Safe Sleep, you can have a PowerPC like sleep time of around 5 to 8 seconds.

Disabling Safe Sleep
To disable safe sleep, run the two following commands in Terminal:

sudo pmset -a hibernatemode 0
sudo nvram “use-nvramrc?”=false

Reboot your Mac and upon resume issue the following command to delete the sleep image from your Hard Disk and free some room.

sudo rm /var/vm/sleepimage

Disadvantages
I’ve been disabling safe sleep for years, ever since I first got an Intel Mac, and have had no issues apart from:
If your battery gets too low, eg below 5%, Safe Sleep will save your session to disk. Without safe sleep, the Mac battery will be drained and it  will be as if you had switched it off.
So before you try this, ask yourself, how often do you let your MacBook run out of power?

Re-enabling Safe Sleep
To switch Safe Sleep back on again, type the following in Terminal:

sudo pmset -a hibernatemode 3
sudo nvram “use-nvramrc?”=true

Reboot and you’re as good as new!



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Andrew Gribben @grib