Is the 50 watt PC possible using commodity parts?

Is the 50 watt PC possible using commodity parts?

Summary: I've been testing a bunch of systems from AMD and Intel in the last few months trying to build the ultimate low-power PC using commodity components and I can say I've gotten close.  I wanted to get to the magic 50W marker at least for idle power consumption which is very important for desktop computers because they spend most of their time close to idle and this is essential for a PC that stays on close to 24 hours a day.

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I've been testing a bunch of systems from AMD and Intel in the last few months trying to build the ultimate low-power PC using commodity components and I can say I've gotten close.  I wanted to get to the magic 50W marker at least for idle power consumption which is very important for desktop computers because they spend most of their time close to idle and this is essential for a PC that stays on close to 24 hours a day.  Keeping the peak power consumption below the 100W marker is also important if you're trying to contribute to medical research projects like folding at home.

The good news I can report is that I got very close and what allowed me to get close to the 50W marker is a high-efficiency power supply though it looks like it still isn't small enough.

First I will disclose the shared components and methodology on the test systems

  • SeaSonic 330W S12 PSU
  • Two DDR2-667 DIMMs
  • 120mm chassis fan (1 watt)
  • 3.5" Seagate Barracuda 160 GB 7200 RPM HDD (on AMD systems)
  • 3.5" Seagate Barracuda 500 GB 7200 RPM HDD (on Intel systems).  This drive HDD uses one watt more than the 160 GB model.
  • 16x DVD +/- R/RW burner
  • USB keyboard
  • USB mouse
  • Peak CPU loads generated with WPrime

PC power consumption at system level Note a 1 watt handicap on the Intel based systems from HDD difference.

To get an idea of how these CPUs perform, Tomshardware has this database of speed comparisons between a whole slew of systems.  Note that the AMD BE-2350 and Intel E6750 2.66 GHz processor are highlighted in red on that comparison chart.  The AMD BE-2350 based system is slower but its peak power consumption is higher than the two Intel CPUs.  I haven't had time to test an Intel E2160 1.8 GHz processor yet but that processor takes even less power than the relatively new Intel E6750 2.66 GHz processor.

The AMD BE-2350 "45 watt TDP" low-power processor designed for the HTPC (Home Theater PC) market does indeed idle at the lowest power level but it's not much lower than the other systems.  The Intel GD965WH motherboard is an older board based on the G965 which had a much less efficient chipset which was fixed with the "3-series" chipset motherboards like the G33 and P35 motherboards.

The Gigabyte motherboard in the chart above is based on an Intel G33 integrated graphics chipset motherboard and coupled with a new Intel E6750 2.66 GHz CPU it was able to show some impressive energy efficiency and performance.  When the CPU voltage was dropped from the normal 1.25V to 1.0V and locked to a 6x CPU multiplier forcing the CPU to operate at a constant 2.0 GHz clock speed, it produced some stellar idle and peak power measurements of 52W and 63W.  That would put it in to the notebook range.  With a much smaller power supply, we could easily see low 40s on idle wattage.

It is interesting to note that most review sites on the web are measuring 60 watts or more for the AMD BE-2350 system and that's almost certainly due to the fact that they're using larger power supplies.  Because I'm using a 330 watt power supply, I'm at about 15% of the rated capacity which already puts me below the ideal 25% to 75% range that a power supply operates at.  So even if my power supply is 80% or more efficient, it might only be 65% efficient at 15% utilization.  If someone uses a 500 watt power supply, then they're only operating at 10% utilization which drops down in efficiency even worse which is why I'm one of the few people measuring well below 50 watts.  If I can find a very efficient 150 watt PSU which takes me out of the commodity market, then I can get 85% efficiency, then I can get my idle power consumption down into the 40 watt range.

Topics: Intel, Hardware, Processors

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39 comments
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  • These would be nice, but...

    How much do they cost when contributing to something like folding.

    Would I be better off at using a series of cheap Celeron systems.

    Or if I want to swat folding and rack up massive points, should I consider a nice quad core system or two that have onboard video.

    Just for those who want to really kill without the draw of power, have you considered "Diskless Folding?"

    Random thought...
    NewEgg now lists energy efficient power supplies: http://tinyurl.com/2jq5uc
    nucrash
    • Celerons use more power

      Celerons use more power and give you less performance so it would not be a good idea.
      georgeou
      • What about Quad Core?

        Or was that true about the power draw being more than double of a Dual Core?

        I would be interested in this if I could build one of these rigs for under $200 or so.

        Keep in mind, I don't need a hard drive or optical drive or a video card for that matter. I only need the processor, mainboard, RAM, and power supply. That should cut my voltage down a hair or two.

        Then again, I need to check to see if my folding solution can handle multiple cores.
        nucrash
        • Quad-cores on well threaded software will always be better

          Quad-cores on well threaded software will always be better for continuous running applications. I'm not sure how well Folding @ Home scales multi-core, I believe it does scale well. The CPU power consumption might be twice as high as a dual-core, but the rest of the system is more or less the same so you're going to do twice as much work for far less than twice the power.
          georgeou
  • Intel vs. AMD on power consumption

    Interesting that you found that an Intel CPU + motherboard consumed less power than an AMD CPU + motherboard. When tomshardware built their solar powered desktop, they seemed to indicate that the Intel CPU alone consumed less power than the AMD CPU alone. But once they took the motherboard into account, they got better results from the AMD platform:
    http://www.tomshardware.com/2007/09/13/hardware_components/page7.html

    I wonder if it had to do with the specific CPUs you chose...
    t_mohajir
    • My CPUs and motherboards were loaned to me from Intel and AMD

      My CPUs and motherboards were loaned to me from Intel and AMD as their best low-power solutions.
      georgeou
  • RE: Is the 50 watt PC possible using commodity parts?

    George,
    When you present facts without any bias, your stories are very good. Keep writing that way.
    mrOSX
  • RE: Is the 50 watt PC possible using commodity parts?

    I suspect the reviewers findings are skewed due to the software being used. It is decidedly biased toward the Intel architecture. The actual findings should be that the AMD CPU at idle is considerably more efficient and the INTEL motherboard and RAM controller knock the Intel offerings in left field as far as energy consumption over long term use is concerned.

    Software should not be used at all as a power indicator but external metering is the only true and unbiased methodology. Even then a reviewers bias can be reflected by WHEN the measurements are taken.
    ONEstar
    • FYI, this is being measured at the plug with a power meter

      FYI, this is being measured at the plug with a power meter for the entire system. That includes the CPU, memory controller, memory, the kitchen sink.
      georgeou
      • If that is true

        If that is true, you have one of the most inefficient BE-2350s on the market....or your choice of motherboard is sucking some serious power.
        ONEstar
        • Other reviews are at 60W plus with BE-2350. I'm at 52W with BE-2350

          Other reviews are at 60W plus with BE-2350. I'm at 52W with BE-2350 so I'm doing much better. Go re-read those other reviews again and you'll see them more closely align to my numbers. I've provided the parts list and methodology and it's plainly clear that my numbers are legit.
          georgeou
  • The Light Bulb

    I have actually achieved a computer that only uses 23W of power. Yes it's true!

    I installed an Opteron CPU inside of a 23W flourescent bulb. I then took my stylus from my Treo and use it to "write" on the bulb itself instead of attaching a keyboard. I use a string to attach the stylus so I never lose it.

    For a mouse, I installed special gyros. Instead of a mouse, I simply wave the bulb in the air.

    For a CD drive, I take existing CD's and make the hole bigger. Using a box cutter, instead of a hole-cutter saw to conserve power, I score and score and then pop the ring out to make the hole bigger. Then I screw the lightbulb into the CD.

    It's really great, and easily fits into a large pants pocket. Unfortunately, sometimes I forget its in my pocket, and I take a nap. I roll over and my "computer" shatters, thus forcing me to rebuild a new one. But it's not that hard to do.
    yyuko9
  • Good post George.

    Very interesting read. I will certainly be factoring in power consumption of parts the next time I upgrade.

    This is more your style. Trying to disprove FUD is futile..
    Bozzer
    • Thanks

      More coming like this, though I can't promise I won't call out any company that misleads the press and people.
      georgeou
  • figures

    15 web sites have posted numbers showing AMD winning PPW,you claim this applies to folding yet you use something else to do the test,then do a test that the power supply you pick by your own admission can affect. Im sorry but thats not messureing the cpu power consuption it messuring platform Consumption,based on the power supply you picked,since you attack AMD daily and constantly show numbers in worst case scenario for AMD ,It would be my guess you just did it again.
    AMD OPTERON
    • re: figures

      "15 web sites have posted numbers showing AMD winning PPW,you claim this applies to folding yet you use something else to do the test,then do a test that the power supply you pick by your own admission can affect. Im sorry but thats not messureing the cpu power consuption it messuring platform Consumption,based on the power supply you picked,since you attack AMD daily and constantly show numbers in worst case scenario for AMD ,It would be my guess you just did it again."

      It's a pity that Apple doesn't use AMD processors in their computers. If they did, you could double the value of your rants.
      M.R. Kennedy
      • Nah, because 0 * 2 is still 0.

        [i]It's a pity that Apple doesn't use AMD processors in their computers. If they did, you could double the value of your rants.[/i]
        Hallowed are the Ori
  • IF

    If Apple used AMD chips...and Intel did not coerce the major system builders to buy Intel only, then there might not be an Intel.

    That would be bad for everyone except AMD.
    Imagine a $1000 AMD6000?
    ONEstar
  • P35 System

    I have just built a P35 system with a 7600GS video card and I am seeing 72 watts at idle which seems consistent with your numbers. Since the video is so wimpy and my video needs are so low, I'm wondering if I should have gone the G33 route and just added another Gig of ram.

    Also, thanks for these article and many others over the last year or so. It was 31 years ago that I built my first PC and I may not have done it again without all the info you provide.
    kmatzen9
  • Is it necessary to save so much power ?

    I do think that they are better place to save power and even if my computer with it's dual quad-core xeon uses more than 200W I still want it to be avail in a seconds when I need it. So having my hard drive making me wait 5 seconds, my monitor slowly coming back (I still use plain 21in Sony CRT) is something frustrating. I would dare to save power if they would make power management something transparent; Reduced Disk Speed instead. Energy economy technique used today are just technology limitation. If they would build better enginered products whe wouldn't need energy savers.
    Shad4Ever