[MacTUG] Different energy consumptions depending on how 'sleep' is initiated

[Steve Hellyer]

Hi Don,

Definitely try and help here as much as possible. :-)

I have one of those Kill-A-Watts as well. It's been a great help for me.
Official specs for Apple hardware are at http://www.apple.com/environment/resources/specs.html

Your examples look very reasonable to me.  The 40w entry would be the  
display
turning off but the CPU and drive are still running. This is called  
idle mode.

Power supply maximum continuous power rating 200 W

Mode			100V	115V	230V
Off			1.44 W	1.46 W	1.43 W
Sleep – WOL off		1.92 W	1.98 W	2.02 W
Sleep – WOL on		2.27 W	2.37 W	2.40 W
Idle – Display off	48.7 W	48.7W	47.9 W
Idle – Display on	85.4 W	84.4 W	82.3 W

WOL = Wake On LAN support.

Also have a look at this article...
http://support.apple.com/kb/HT1543

PMSET commands (note: must be run as run as root)
http://developer.apple.com/documentation/Darwin/Reference/ManPages/man1/pmset.1.html

I do hope this helps.

Steve

On 5-Nov-08, at 12:50 PM, Don Duff-McCracken wrote:

> Hi Guys
>
> I am hoping that Steve H. is still reading these postings as an Apple
> Engineer could likely help me out.
>
> As part of our green computing initiatives, I am looking at ensuring
> our macs are sleeping when not in use. We have bought some great
> little devices that provide realtime energy use ("kill-a-watt power
> monitor" only $30 each! http://store.greengadgets.ca/products/P4400.html)
>  and one thing I have noticed is that how the mac is put to sleep
> radically alters its energy use.
>
> For example
>
>  ~80 watts -- Regular consumption of a 20" newer imac
> ~40 watts -- computer goes to sleep on its own via settings in energy
> saver control panel (set up to have the display, and the cpu go to
> sleep and the hard drive to stop whenever possible)
> ~02 watts -- (yes 2 watts!) put the computer to sleep manually from
> the apple menu or the "Are you sure you want to shut down..." dialog  
> box
> ~02 watts -- put the computer to sleep remotely using Remote Desktop
>
> As you can see, this is a radical difference in energy use!
>
> What I want is to not have to rely on Remote Desktop. I would like to
> use the energy saver settings and tweak them using the "pmset"
> command. I have been playing with it to no avail.
>
> Does anyone -- Ahhem, Steve -- have any suggestions?
>
> Thanks
> (former mactugger) Don
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