Hitting 50W peak on a dual-core desktop computer

Hitting 50W peak on a dual-core desktop computer

Summary: The 50W no-compromise dual-core commodity desktop PC is now a reality!I have some great news for the green computing world.

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TOPICS: Hardware, Processors
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The 50W no-compromise dual-core commodity desktop PC is now a reality!I have some great news for the green computing world.  The 50W no-compromise dual-core commodity desktop PC is now a reality!  It all started a few months back when I looked in to the possibility of building a main stream dual-core desktop computer that can drop under 50 watts idle but now I've answered that question beyond all expectations.  Using a 220W Sparkle SPI220LE "80 Plus" efficient power supply, an Intel E2140 1.6 GHz dual-core CPU running at lower-than-spec 0.95 volts, and a Gigabyte G33M-DS2R motherboard, the system comes in just under 50 watts at *PEAK* CPU load generated by WPrime running 2 threads.  If I could only find a smaller 100 watt 80 Plus power supply and hit the optimum 50% loading at peak power consumption, then it might be possible to get peak system loads down to around 45 watts.

At idle the system uses 41 watts which is actually one watt higher than my sub-$400 All-in-One LCD PC with an ECS 945GCT-M motherboard and an Intel E2180 2.0 GHz dual-core running at stock speeds and voltage.  It turns out that this G33M-DS2R board with E2140 CPU running at stock speeds and voltage has an idle system power of 46 watts which is 6 watts higher than the ECS board with E2180.  This was surprising to me since the new G33 chipset has a more energy efficient memory controller than the 945 chipset.

Possible explanations are the fact that the G33-based motherboard was running the memory at 400 MHz base clock (DDR2-800 memory) whereas the 945-based motherboard was running the memory at 200 MHz.  One other factor is the fact that the Gigabyte G33M-DS2R Intel G33-based motherboard has a 6-port SATA ICH9R RAID controller along with a few more memory and PCI ports.  This leads me to think that the combination 2x the memory clock and more components translates to an additional 6 watts of power consumption.

The following idle/peak power consumption charts are from data I collected.

* SPI SPI220LE 220W 80+ PSU ** No system fan which saves 1W power

Gigabyte with Intel CPU = G33M-DS2R motherboard Gigabyte AMD CPU = MA69GM-S2H motherboard MSI with AMD CPU = K9AGM2-FIH motherboard

Topics: Hardware, Processors

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69 comments
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  • Needs a Part 2

    Part 2 being the performance per watt. Obviously the 1.2 and 1.33 processors lead the way in least power consumption, but when the power consumption per clock cycle counts, whose chip do you want in your system?

    I would think that a Quad core would still be more energy efficient over all. That is just my opinion though.

    Then again, when you are just surfing the internet. You don't always need a tank to get from point A to point B when a motorcycle will suffice.
    nucrash
    • Performance per clock leader would be an Intel Yorkfield

      Performance per clock leader would be an Intel "Yorkfield" 45nm quad-core running at 3 GHz on any MicroATX 3-series chipset.

      From the official power benchmark list (http://blogs.zdnet.com/Ou/?p=927), the 3 GHz 5400 series CPU on 5400 chipset is the leader, but no one has posted any Yorkfield 3.0 numbers yet which would probably do about 40% better than the best.
      georgeou
  • that's good news

    I'm not so concerned about being green, but more about creating fan less computers that can sit on the shelf or in a cabinet in the living room. So far the fan noise and the heat kept them away.
    Linux Geek
    • Green has two meanings

      There's the saving of green backs every month, and then there's keeping the earth green. Take your pick :).
      georgeou
    • This isn't fanless, but it is relatively noiseless

      This isn't fanless, but it is relatively noiseless because you don't need to worry about high RPMs.
      georgeou
    • Replace the constant speed fan ...

      ... with a temperature-controlled variable speed fan. Most computer manufacturers don't use them because they cost a buck or two more. Some years ago I replaced the power supply fan in the power supply of my old tower case with a variable speed fan. To-date, it has never run at full speed and is nearly inaudible.
      Tony R.
      • All Intel retail fans come with 4-pin variable speed fans

        All Intel retail fans come with 4-pin variable speed fans. Even the cheap $88 motherboard/dual-core E2180 deal I got included the retail box which comes with a fairly silent fan.
        georgeou
  • Is it quiet?

    That's another issue I have with systems, is noise. I want a low
    consumption, low noise machine. I know most systems out there
    today are fairly quiet, but not as quiet as they could be.
    NoPumpGas
    • Lower power allows you to use fewer and slower fans

      Lower power allows you to use fewer and slower fans which translates to little or no noise. This particular setup has almost no noise since the CPU fan operates at a very slow RPM and it doesn't really need to speed up since the CPU never gets that hot.
      georgeou
      • Good enough

        I'll probably try and build one then. I want a powerful Vista machine that is
        quiet.

        The bar has been set with my Mac Pro, which is a powerful machine but very,
        very quiet. Of course, it has ridiculously large CPU sinks and huge fans that
        turn rather slowly but move allot of air. In fact it has heat sinks on all the
        Memory chips as well.
        NoPumpGas
  • Disabling Peripherals In The Bios

    George, Have you tried going to the bios setup and disabling any unneeded peripherals such as the raid controller since you stated that may be a source of excess power consumption?
    jeffaaa6
    • RAID is not enabled

      RAID is not enabled. But in general, the bigger the motherboard the more power it draws. When you have fewer PCI slots and memory slots, the motherboard almost always uses less power.

      I could have slashed another 7W off by using a laptop drive or slashed 4W off by using the Western Digital GreenPower drives. If I can ever find a 100W 80 Plus PSU, I can probably get much better power efficiency and slash another 5W. When Intel eventually switches to 45nm chips for their value line by the end of 2008, then it will be possible to slash the power even more.
      georgeou
      • George I have an interesting test for you...

        Test what the total powered used to accomplish a task.

        1) Start with a captured video (home movie)
        2) Encode and burn to a DVD
        3) Measure the total power consumed.

        Do Stesp 1-3 for the high end and low end system.
        mrOSX
        • Encoding would be the only CPU intensive task

          Encoding would be the only CPU intensive task, 100% if it's an efficient codec. You can pretty much just use the peak power consumption numbers for a pretty darn accurate estimate.
          georgeou
  • RE: Hitting 50W peak on a dual-core desktop computer

    Want a real green machine? Try charcoal and birch bark!
    Just a treehugger gag!
    morwen
  • Does this include...

    hard drive and cd-rom usage? Or what about inserting a USB device drawing power from the bus?
    bjbrock
    • Hard drive usage will add about 4W

      Hard drive usage will add about 4W to the system. So in theory if you were thrashing the hard drive with IO read/write WHILE the CPU is operating at 100% (which is unlikely), the power will go up to 54W. Optical drive was connected but not active but that will add a few watts if you were burning a DVD or something. But again, you can't burn DVDs when CPU is 100% since that will likely ruin the disk so you won't realistically go over 50W.
      georgeou
  • RE: Hitting 50W peak on a dual-core desktop computer

    Very cool George... Would this machine handle the Media Center type duties?
    rvanrooyen
    • Yes, but G33 based boards aren't as optimized for DVD quality

      Yes, but Intel G33 based boards aren't as optimized for DVD quality and it has the same problem as AMD 690G based boards. They both fail the HQV benchmark on quality. However, the problems are only noticeable on some DVD titles especially Anime. If you use Power DVD (bundled OEM version with DVD burners) and set it to Force Bob mode on deinterlacing, the problem mostly goes away.

      So short answer is yes it will handle Media Center just fine but you can get vastly superior quality for DVD, HD DVD, Blu-ray, and games if you buy something like an NVIDIA 8600 or ATI 2600 video card. This would jack up the power usage by about 20 watts though.
      georgeou
  • RE: Hitting 50W peak on a dual-core desktop computer

    Also, could you post the exact specs on this machine? I didn't see disk drives etc
    rvanrooyen