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Power IT

Five PC Power Myths Debunked 551

snydeq writes "Turning off PCs during periods of inactivity can save companies between $25 and $75 per PC per year, according to Energy Star, savings that can add up quickly for large organizations. Yet most organizations remain behind the times on PC power management, in large part due to common misperceptions about PC power, writes InfoWorld's Ted Samson, who outlines five PC power myths debunked in a recent report from Forrester, ranging from the energy savings of screen savers, to the energy draw of powering up, to the difficulties of issuing patches to systems in lower-power states."
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Five PC Power Myths Debunked

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  • Word (Score:5, Informative)

    by IceCreamGuy ( 904648 ) on Friday December 12, 2008 @10:46AM (#26090027) Homepage
    All through college I left my PC on 24/7, however now that I'm paying the bill I have thermal throttling and the other new power-saving standards all turned on, and I turn everything off (router, modem and all) entirely when I'm not using it. It's odd the way people look at it; at work some users say "Well I never leave it on at night because I know that it makes the computer die quicker" and some people say "Well I never turn it off because I want it to last longer." I think the truth is that modern hardware really can handle both philosophies and it's just a matter of convenience vs. power costs at this point.
  • Bad economics (Score:5, Informative)

    by Spazmania ( 174582 ) on Friday December 12, 2008 @10:50AM (#26090087) Homepage

    1.42kw for the computer to run overnight has a cost of around 10 cents to the company.

    Waiting 5 minutes for your PC to boot at the federal minimum wage of $6.55 per hour has a cost of around 55 cents to the company.

    It costs the company at least 5 times as much to have you boot your PC in the morning as it does to let it run overnight.

  • Typo? Pshaw! (Score:5, Informative)

    by ClayJar ( 126217 ) on Friday December 12, 2008 @11:00AM (#26090213) Homepage

    Of the four instances in which watts were referenced (directly or in compound units), three are completely boneheadedly wrong:

    Forrester debunks this myth as follows: The average desktop draws 89 watts per hour. If it's left on overnight for 16 hours, it consumes 1.42kW. It's impossible for the power surge that occurs when powering on a PC to rival that figure: "You would be drawing energy at a rate of 17 kWh -- the equivalent of 44 HP DL580 servers at 100 percent utilization. Moreover, the average US wall outlet can only provide 1.8 kW of draw, which is about one-tenth of what the power surge would require."

    They should be:

    • 89 watts
    • 1.42 kWh
    • 17 kW
    • (1.8 kW is correct.)

    You *can't* call it a typo when they are perfectly backward in three out of four incidents. And you can't call it "They just got it backward..." when they got it right once. You must conclude, therefore, that they have almost no grasp whatsoever of units.

  • by jellomizer ( 103300 ) on Friday December 12, 2008 @11:04AM (#26090285)

    Well 15 minutes of power on and power off is a bit exaggerated (unless you really misconfigure linux). Normally for most business PC it takes about 1 minute to power on and power off doesn't need to be counted as you can perform this action without you actually there you hit shutdown and it does its thing.

    That being said...

    >>> (20.00/60)*5*(48+(4/5))

    Assuming 20.00 an hour average wage (40k per year)
    We divide this by 60 to give the rate per minute.
    Multiply this by 5 for the five work day week.
    Then multiply it by 48 and 4/5 for fifty work weeks (2 week vacation) a year and subtract one extra week and a day for holidays (New Years, Memorial Day, Independence Day, Labor Day, Thanksgiving, Christmas) .

    So in theory it is more expensive to power on every day...
    However the human factor is not factored in even for your 10 minute days of inactivity. At the beginning of the day most people are not at 100%. They will power on the computer, take off their jackets, get some coffee, put their lunches in the kitchen, greet some people, clean their desk up a bit. Also any loss productive during 10 minutes can usually be made up.

    So you might as well power off at the end of the day and save some power and be better for the environment.

  • Any modern PC can S3 suspend.

    S3 suspend cuts power use by 95% and the PC resumes *INSTANTLY*.

    I can S3 suspend my laptop and have it run off the battery for over a week - open it up and I am back where I left off in about 2-3 seconds.

    There is no argument against having an IT policy MANDATING S3 suspend. Hell you can even automate it to do it by default every day at 6 PM unless the PC is in use (easily checked by screensaver APIs).

  • by fermion ( 181285 ) on Friday December 12, 2008 @11:13AM (#26090461) Homepage Journal
    These are the two that are the biggest problem due to power off, and power management, one the OS level, should handle this. I have all my machines automatically shut after a few hours in inactivity. But most virus checkers only have time of day settings, and there are no hooks from automatic shutdown to these important services that need to be run every day. Sure you can push an update, but that requires the machine be in sleep or hibernate, not shutdown. For small number of machines, this can be done manually once a week, but this is something that needs to be built into future OS if the OS is going to have weekly updates that require a restart.

    Then there is the issue of starting up for the day. Shutdown can happen automatically, but startup should be initiated by the user. Sometimes it does take several minutes to connect to online volumes or for MS to do whatever it does. I have seen a couple machines take a very long time to boot. Again, I think hibernate is a good compromise, but there must be hooks in the system to allow virus updates and other patches.

    All this means that all applications must be closed in case a automatic update occurs, something I almost never do on my machines. I put them to sleep, but my apps are open. On my MS Windows machine, this every once in while means I have to start all over again loading apps.

  • Re:Winter (Score:5, Informative)

    by mr_matticus ( 928346 ) on Friday December 12, 2008 @11:28AM (#26090689)

    Depends on where you live and what you're heating. Ignoring regional variations in costs and heating needs, a natural gas forced-air system will heat the entire house, requiring substantially more money than electric radiators, which are per-room.

    Combine this with places where electricity is remarkably cheap (e.g. large hydro works) and natural gas is expensive (e.g. all imported), and you are better off heating with electricity. Even if you live in an area with cheap natural gas, electric radiators allowing you to heat only the spaces you're using may end up saving you money over heating a whole house at night to keep the temperature toasty in two occupied bedrooms. This is especially true in Mediterranean climates, where natural indoor temperatures remain above 12 C even in the winter, thus requiring a comparatively small "bump" to hit the desired 20-22 C range.

    In any case, waste heat generated by electronics is salutary, so long as the electronics are being used for their primary purpose as well.

  • Re:The units! (Score:5, Informative)

    by madbavarian ( 1316065 ) on Friday December 12, 2008 @11:32AM (#26090765)
    Same here. This is the point I stopped reading too. Anybody that thinks that a PC takes 89 watts per hour isn't worth listening to for technical advice. The next line just cemented it for me "If it's left on overnight for 16 hours, it consumes 1.42kW." Aaarrrrg. How did our basic science education go so wrong??? Please tell me that this guy is really a movie reviewer that is sitting in for the technical person as they take the holidays off.
  • by AviLazar ( 741826 ) on Friday December 12, 2008 @11:41AM (#26090933) Journal
    Last I heard monitors were the biggest cost on the average computer (not some twinked out machine). Given that - compromise - power down your monitor.
  • Re:Typo? Pshaw! (Score:3, Informative)

    by julesh ( 229690 ) on Friday December 12, 2008 @11:47AM (#26091051)

    Not only that, but "watts per hour" doesn't actually make any sense at all. Unless we're talking about something that is gradually consuming more and more power as time passes.

  • by nobodylocalhost ( 1343981 ) on Friday December 12, 2008 @11:53AM (#26091135)

    I totally agree, S3 suspend really hasn't matured to the point where it can be used without repercussions. Lots of software tend to crash when waking up from S3 suspend, or even S2 standby. Especially those god awful wireless network card drivers. And once they go down, your network card simply wont be active without a restart due to sudden jump in time. Too many things can go wrong on HAL. Even when using linux. Also, some hardware simply need the bios to re-initialize them, OS just wont do the trick and they stay at S3 even though the rest of the computer is back to active mode. I think we should make the "green" features functional before preaching about using them.

  • Re:Winter (Score:1, Informative)

    by Anonymous Coward on Friday December 12, 2008 @12:01PM (#26091259)
    shut the fuck up
  • Not what it seems. (Score:2, Informative)

    by KennyMillar ( 813395 ) * on Friday December 12, 2008 @12:18PM (#26091537) Homepage Journal
    The linked article is nothing more than a poorly disguised plug for an expensive Forrestor research paper.
  • by WRSaunders ( 910173 ) on Friday December 12, 2008 @12:48PM (#26091989)
    Exactly true. The IT installed startup script takes 10 minutes to run. Anti-virus scans of memory and installation of proxies and filters maxes out hard disk throughput so that users see no responsiveness to their inputs. Happens once or twice, and the user never turns the machine off again. Sleep loses network connections, and re-establishing them causes all these vampire robots to fire up again. Once one user figures this out, and shows their friends, nobody puts computers to sleep again. Now if IT didn't want to monopolize the user's computer ... . Never mind, that's not going to happen.
  • by MostAwesomeDude ( 980382 ) on Friday December 12, 2008 @01:42PM (#26092809) Homepage

    Unfortunately, I can't remember the exact chipsets, but some Ethernet cards are capable of WoL from any valid IP they had before being shut down, and some are capable of WoL from MAC address only, ignoring IP. This means that, if you set up your firewall right, you can WoL from the WAN/Internet with no problems.

    I personally leave my firewall on all the time, and my fileserver suspends itself after a few hours of boringness. I have a handful of knocks on the firewall that can shutdown, restart, wake up, or sleep the fileserver.

  • by oasisbob ( 460665 ) on Friday December 12, 2008 @01:50PM (#26092911)

    But suspending doesn't drop power demand as much as shutting down

    This varies a lot PC to PC.

    At work, I'm just now implementing power savings. The first strategy considered was to use a schedule and shut the computers off at night, and turn them on in the morning. I'm really glad we didn't go that way.

    Real-life measurements are crucial. One of our standard workstations (Lenovo 8808 + 17" LCD) draws 120W. With the monitor and PC in standby, the draw is only 3W.

    That's close enough for me.

  • by oasisbob ( 460665 ) on Friday December 12, 2008 @01:59PM (#26093063)

    Last time I checked (and it has been a little while since I checked, so I could be wrong) there was no way to push out power settings with a GPO.

    Almost true. Mostly true? Or used to be true. Or, in a perfect utopia, this isn't true anymore.

    There's a tool from Energystar called EZ GPO [] which lets you install an power managment agent on the client, and manage it using an administrative template. In my experience, it works pretty well. It's a bit weird though: for some configurations, the tool doesn't use the win API, and has broken in the past with Windows Updates.

    AFAIK, Windows 2008, or a Vista workstation on a 2k3 domain can be used to manage power savings on XP if the client-side extensions [] are installed.

    Also, some expensive tools like LANDesk support power policies. Not ideal for most people ($$$$), but if you're already using "enterprise" management tools, worth checking out.

  • by Anonymous Coward on Friday December 12, 2008 @02:22PM (#26093419)

    This article ignores how commercial facilities are charged by power companies. Commercial facilities are not priced the same way residential power consumption is priced. Ever wonder why all the sky scrapers downtown have their lights on all night? It's because it's cheaper to leave them on than save power and turn them off. Power companies charge commercial facilities based on how much "surge" (I might have the technical term wrong here) they produce. Meaning, if everyone comes into work in the morning and turns their lights and computers on, that produces a large "surge". If everyone leaves the lights and computers on all night, that produces less "surge" and therefore a smaller power bill.

  • by mollymoo ( 202721 ) on Friday December 12, 2008 @09:54PM (#26099131) Journal

    Too bad all major HD manufactures claim 10,000 power cycles, and many power saving settings will turn off a HD w/o doing anything else.

    That number sounded wrong, so I checked some typical 3.5" desktop hard drives. These are the first three I looked at.

    Seagate 7200.10 [] : 50 000 start/stop cycles.
    WD Caviar Blue [] : 50 000 start/stop cycles.
    Hitachi Deskstar T7K500 [] : 50 000 start/stop cycles.

    Since Seagate bought Maxtor and Hitachi bought IBM's storage division, those three are all the major manufacturers of desktop hard drives.

    Head wear is the limitation with stopping and starting typical desktop hard drives. Desktop drives typically park their heads on a laser-etched landing zone at the centre of the platters. Spinning up the drive causes wear as the heads drag on the surface until the air cushion is developed - the laser etching roughens the surface, allowing the heads to slide more easily. Most laptop drives park their heads on a ramp, so the platters can spin up with no head contact and can take an order of magnitude more cycles (specified as load/unload).

"Even if you're on the right track, you'll get run over if you just sit there." -- Will Rogers