Configuring pmset options for SSD

Discussion in 'MacBook' started by benwiggy, Mar 4, 2013.

  1. benwiggy macrumors 68020

    Joined:
    Jun 15, 2012
    #1
    I have an Early 2009 MacBook, 6Gb RAM, with a 240Gb SSD (OCZ Vertex Plus R2).

    There are many pages advising people who have replaced their hard drive with an SSD to change some of the Power Management settings, using the Terminal pmset command.

    The main suggestions are

    • to turn off Sudden Motion Sensor (as SSDs don't need such protection against mechanical movement), which seems fair enough;

      to change the hibernation state, so that OS X doesn't save a 6Gb sleep image of the memory to the SSD.
    Now, given that it's a 2009 MacBook, which I'm likely to get another two years out of; and it's only 6Gb out of 240Gb (I still have over 100Gb free): I'm not so worried about using up my precious SSD writes, as I expect the drive will still be good by the time I get a new Mac.

    However, I'm more concerned with maximising battery life (and I would rather that my un-saved docs were retained and not lost when the battery dies).

    The pmset manual suggests that the "standby" parameter can be used to set deep hibernation at some point after sleep is started. But my Mac doesn't seem to respond to the standby or standbydelay parameters.
    As it is, my MacBook has always trickled down its charge if I sleep it, rather than turning it off.

    My current settings are:
    Code:
    Currently in use:
     hibernatemode        3
     acwake               0
     lidwake              1
     halfdim              1
     sleep                15
     ttyskeepawake        1
     sms                  0
     hibernatefile        /var/vm/sleepimage
     disksleep            10
     displaysleep         10
    Anyone know anything about this stuff? All the webpages I've seen just say "you don't want a hibernation sleep image".
     
  2. benwiggy thread starter macrumors 68020

    Joined:
    Jun 15, 2012
    #2
    On the basis of the stuff in this post
    it seems that my Mac doesn't support standby; though all the terminology is a bit confusing (standby, sleep, hibernation, nap, etc).

    As a result, I thought that hibernation mode 25 wouldn't work well: but actually it may do after all. That's certainly the one to go for if you want more battery life while the lid is closed.

    As a result, the little glowing light goes off after a while, and you have to press the Power button to wake the computer. There's a bit of a delay, but the machine state is restored -- it's not a restart.
     
  3. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #3
    The "deep sleep" or "stand by mode" is not there on your machince since it is a 2009. See this Apple doc that shows supported machines.

    On the sleep image issue... IMO just leave it alone at the default setting. This was a misguided concern of early SSD users that the sleep image added unnecessary write cycles to the drive. You only encounter a sleep image write when you let your battery run down below 20% to data is not lost when the system shuts down on its own. During normal usage and a normal "sleep" from closing the lid does not create a sleep image.

    We were just discussing this issue earlier in this thread. Start from post #2021 and read to the end of the thread.
     

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