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What is actually running in sleep mode?


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Can someone tell me what is actually running while I'm in sleep mode, I'm interested in conserving power and I'm not sure whether to use scheduler to shutdown and restart my hack or to use sleep and wake (all of which work).

What I would be most interested in is how much power is being used in sleep mode, I can see that all my system fans are still running!

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Useful reply Superhai. Why don't you tell him to go read the f'ing manual or something?


Answer to your original question Lanxxx


Nothing runs in sleep mode, however your RAM is usually kept powered on so your computer will 'wake up' faster.


How to find and change your sleep mode


Open a terminal and type this and hit enter.

pmset -g | grep hibernatemode


The sleep modes are:

  • 0 - Old style sleep mode, with RAM powered on while sleeping, safe sleep disabled, and super-fast wake.
  • 1 - Hibernation mode, with RAM contents written to disk, system totally shut down while “sleeping,” and slower wake up, due to reading the contents of RAM off the hard drive.
  • 3 - The default mode on machines introduced since about fall 2005. RAM is powered on while sleeping, but RAM contents are also written to disk before sleeping. In the event of total power loss, the system enters hibernation mode automatically.
  • 5 - This is the same as mode 1, but it’s for those using secure virtual memory (in System Preferences -> Security).
  • 7 - This is the same as mode 3, but it’s for those using secure virtual memory.
    Once you see which mode you’re presently using, make a note of it.

To set it, type this in the terminal replacing the question mark with one of the numbers above. You'll have to enter your password after you hit enter (it'll prompt you.)

sudo pmset -a hibernatemode ?

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Thanks for the replies

As for what kind of sleep good question my mobo is ga-p35-ds3l all I can tell you is that with leopard originally sleep only worked in s3 mode now it only works in s1 mode. My processor fan remains running, all of the system fans remain active, but hard drives do go to sleep as I can hear them spin back up.

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