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10 IT Power-Saving Myths Debunked

Posted by timothy on from the replace-all-leds-with-cfls dept.

snydeq writes "InfoWorld examines 10 power-saving assumptions IT has been operating under in its quest to rein in energy costs vs. the permanent energy crisis. Under scrutiny, most such assumptions wither. From true CPU efficiency, to the life span effect of power-down frequency on servers, to SSD power consumption, to switching to DC in the datacenter, get the facts before setting your IT energy strategy."

5 of 359 comments (clear)

  1. Sleep != Hibernate by Taimat · · Score: 5, Informative

    Myth No. 6: A notebook doesn't use any power when it's suspended or sleeping. USB devices charge from the notebook's AC adapter. Fact: Sleep (in Vista) or Hibernate mode in XP saves the state of the system to RAM and then maintains the RAM image even though the rest of the system is powered down. Suspend saves the state of the system to hard disk, which reduces the boot time greatly and allows the system to be shut down. Sleeping continues to draw a small amount of power, between 1 and 3 watts, even though the system appears to be inactive. By comparison, Suspend draws less than 1 watt. Even over the course of a year, this difference is probably negligible.

    um... Hibernate != Sleep. Hibernate in XP saves the RAM to the Hard Drive, and powers off. Suspend keeps RAM powered....

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    1. Re:Sleep != Hibernate by afidel · · Score: 5, Informative

      How about build an energy efficient PC! I have a LP AMD 64 x2 with a Geforce 7600GS, 2 HDD's, 2GB of ram and a TV tuner and an 85% efficient PSU and I peak at around 150W, using 140W at idle is insane. For the next generation of games I'm thinking about upgrading to a 9600 GSO but that will up my idle and peak numbers by at 20W so I'm holding off till I get a game that really needs it.

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  2. Re:Questionable grasp on the problem space. by Anonymous Coward · · Score: 5, Informative

    I like how this plays with the following assertion filed under "Myth No. 9: Going to DC power will inevitably save energy."

    "New servers have 95 percent efficient power supplies, so any power savings you might have gotten by going DC is lost in the transmission process."

    So, when it suits his argument, power supply efficiencies range from 50-90% efficency, and are kept hidden by manufacturers. Then, when that doesn't suit his argument, all of a sudden power supplies are at least 95% efficient, and everyone knows that.

    I call shenanigans!

  3. Re:I dunno.. by gnick · · Score: 5, Informative

    FTA:

    Hibernate mode in XP saves the state of the system to RAM and then maintains the RAM image even though the rest of the system is powered down.

    They must be using a different version of XP than I am... When I 'Hibernate' my laptop, it dumps the RAM to a file on the hard drive and then powers off completely. When I 'Stand By' my system, it keeps everything in RAM.

    Maybe they have SP4...

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  4. Re:I dunno.. by snowraver1 · · Score: 5, Informative

    If you are using electric heat, chances are you don't live in a cold climate and pay for air conditioning for much of the year negating any "savings". Here in cold-balls Canada, EVERYONE has centeral heating; it's too expensive to use electricity. That being said, I do agree that datacenters' heat should be used to heat useful things (office bldgs, like you suggest).

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