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Sleep Mode Power Consumption

11985 Views 7 Replies Latest reply: Nov 3, 2008 9:54 AM by S. Kaliko Trapp RSS
Bobbbo Level 3 Level 3 (530 points)
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Aug 11, 2008 3:50 PM
I am interested to know if anyone knows how much a Mac Pro drains from your home AC outlet when the computer is in sleep mode? Someone is suggesting we unplig our computers when not in use to help solve our energy problems. I would guess the computer would draw less than 10mWatts from 120VAC.
Mac Pro 2.66 GHz, MacBook Pro 2.1 GHz, eMac G4, PowerMac G4, Mac OS X (10.4.11)
  • Larry from VA Calculating status...
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    Aug 11, 2008 5:15 PM (in response to Bobbbo)
    I recently measured mine with a "Watts up?" device. The computer itself measures 7.8 watts sleeping. The I measured at the input to the UPS = 30 watts. Connected to the UPS is a cable modem, LinkSys router and the 23" ACD in sleep mode.

    Idle run mode measured 172 watts for the computer and 228 watts measured at the input to the UPS. Idle running power factor measured around .9, not too shabby for a computer!

    Mac Pro startup or wake-up from sleep draws around 10-11 amps very very briefly at a low enough power factor that the startup peak watts measured 269 from startup and 222 waking from sleep.

    AC Main = 120 VAC, true power wattage measurement accuracy on the "Watts up?" is around +/- 1%.
    2008 2.8G MacPro 8GB RAM 3x500GB WD Drives, Mac OS X (10.5.4), NVIDIA 8800GT GPU 23" ACD RS1500 UPS
  • Larry from VA Level 1 Level 1 (30 points)
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    Aug 11, 2008 5:23 PM (in response to Larry from VA)
    One more datapoint: My Mac Pro measures 3.8 watts turned completely off but still plugged in.
    2008 2.8G MacPro 8GB RAM 3x500GB WD Drives, Mac OS X (10.5.4), NVIDIA 8800GT GPU 23" ACD RS1500 UPS
  • Larry from VA Level 1 Level 1 (30 points)
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    Aug 11, 2008 5:47 PM (in response to Bobbbo)
    The difference between power-up and waking from sleep is pretty negligible. You don't re-boot from a sleep condition but you do re-load RAM image and start up as many drives as you have mounted. The difference (between cold start and wake from sleep) measured about 40 peak watts over milliseconds.

    I set the sleep idle timer for around 3 hours and definitely put it to sleep at night.
    2008 2.8G MacPro 8GB RAM 3x500GB WD Drives, Mac OS X (10.5.4), NVIDIA 8800GT GPU 23" ACD RS1500 UPS
  • traisjames Calculating status...
    Currently Being Moderated
    Oct 14, 2008 10:15 AM (in response to Bobbbo)
    Hi Bobbbo. I have done some testing with my kill-a-watt here at my college and one was that a macbook pro (or macbook's pro) uses about 2 watts of power when in standby. I did all this because my college (Northland College in Ashland, WI) leaves its computers on 24 hours a day M-F, and about 8 hours on weekends, and being in the environmental council, I wanted that changed, so I started compelling number to prove that it would be better to turn them off. I have found that if we go from current usage to optimal usage, we would save about $8000 for the systems alone...not including monitors. (Note that our college has a population of about 750).
    Below is some numbers that I have copied out of an excel file for your view pleasures. Sorry if it looks funny now. the first one is my macbook pro, the second item is my imac 20 inch.

    On Power Off
    Backlight Full or for desktop Backlight at lowest Backlight off Screen Off Averages Estmated power Estmated pow
    User Maker Screen Size Processer Low Processor Hig Processer Lo Processor Hig Processer Low Processor Hig Processer Lo Processor Hig Processer Low Processor Hig Standby Hibernate Shutdown usage per year cost per year
    Travis Apple 15w 28 41 21 36 21 35 18 33 22.00W 36.25W 2 1 132.23 KWH $10.92
    Travis Apple 20w 73 85 50 62 36 48 53.00W 65.00W 2 1 313.14 KWH $25.86

    Ok, it looks really bad, sorry. Let me do this...I uploaded it to my website and you can get directly to it by going to http://travisjames.50webs.com/Print_Area.htm (no WWW...its a weird site). The two other computers listed are laptops. the reason an iMac is on this page is because it has the monitor plugged directly into the system and is using the same power source. When I get a chance, I will put everything I have up there so you can view all my data.

    From the guy with his eye on the sky, Travis
    Macbook Pro, Mac OS X (10.5.5)
  • S. Kaliko Trapp Calculating status...
    Currently Being Moderated
    Nov 3, 2008 9:54 AM (in response to traisjames)
    Thanks, Travis, for the excellent info. Unfortunately, your chart on the website appears to be using some pretty funky formatting rules in the Excel-generated HTML/CSS. Perhaps you could have someone look into fixing it, as the information is very relevant considering the recent push in our universities to reduce electric use. Thanks again for the posting.
    Lots of Macs and Apple tech —, Mac OS X (10.5.5), — Fixing Macs since 1994

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