4 Replies Latest reply: Feb 13, 2012 11:39 AM by Jemster
Jemster Level 1 Level 1

I have an i5 27" iMac and have had for a couple of years, but have been getting a bit paranoid about energy consumption in the house and had a look at the power usage when it sleeps, and when it's active.


I've found that when active, it's using about 120w, if I have energy saving configured to put the computer & display to sleep after x minutes, it then consumes 80w. HOWEVER, if I put it to sleep using the Sleep on the menu, it is a much more efficient sleep and uses only 11w.


So my question is, is it supposed to sleep "properly" when configured to sleep in the energy settings, or is this almost-perfect sleep only meant to be attainable by the Sleep menu (and by scheduled sleep also, that seems to work properly).


I've spent a few hours trying everything to get it to fully sleep on the inactivity timer but all to no avail. I've unplugged all USB devices, just leaving keyboard & BT magic mouse, I've tried starting in safe mode with the left shift key held down, no joy there. I've cleared the "wake for network access" checkbox. Also had a play with pmset, but couldn't get it to do anything better and I'm starting to feel like I'm chasing something impossible here.


I installed narcolepsy, but it insisted on shutting me down every 5 minutes regardless of whether it was in use. I also tried PowerSleep, but it would go to sleep even if iTunes was playing, so no dice there as I permanently have iTunes loaded and don't want it sleeping when I'm playing out to my Airport Express units.


I've read a lot of posts on this, but no one seems to say whether or not the full-sleep should be achievable through the Energy Saver timers and I'm starting to think it's not possible...

iMac, Mac OS X (10.6.8), 27" i5
  • ssls6 Level 4 Level 4

    Mine goes to sleep fully.  What web browser do you use?  I have found some won't let a computer go to sleep as they keep talking to the mothership.  I use safari which does.

  • Jemster Level 1 Level 1

    You are positive? Absolute, silent sleep? On the Energy Saver timer? Ok... Wow... maybe this is possible then.


    No web browser running - I've tried a total clean start (left-shift held down), no applications running, set the sleep timer for 1 minute display and 1 minute computer sleep... waited... display dimmed after 30s, display then went off, that was it, as 'asleep' as it gets (without picking 'Sleep' off the menu).


    Hmm confused now... is there no way of debugging this issue logically? I don't know what else to try, everything is unplugged, machine is cleanly started... are you using Bluetooth?

  • ssls6 Level 4 Level 4

    Maybe sleep to me is different than sleep to you....I can say drives are down, display is down, computer back is cold to the touch.  I don't put a power meter on it so you could be right.

  • Jemster Level 1 Level 1

    Maybe... I know if I click on Sleep, there's an audible click and then absolute silence. If I wait for the energy saving to 'sleep' then it's just the display that goes black and I am fairly sure I can hear the internal drive stepping from time to time and a fan running somewhere.


    Sounds to me like your sleep is different from my sleep ... anyone got any good tips for finding the reason it won't sleep, given all the steps I've tried above?