Power Consumption RRS feed

  • Question

  • Hello,


    I have been thinking about setting up a home server for some time - so the WHS looks like a great option.


    At the moment, I have a small NAS device (for simple file storage). This uses only about 20W (but only contains a single hard drive).


    I would like my WHS to have a second HDD for some redundancy, but what sort of min / max power consumption would I be looking at on (say) a basic "barebones" computer? Would this figure vary much depending upon the system "load"?




    Monday, June 18, 2007 9:42 AM

All replies

  • depends on sevral factors
    firstly as you said
    system load
    power supply used in barebone (average is 500W)

    Monday, June 18, 2007 1:14 PM
  • Using a small form factor case, low wattage CPU, and integrated video you could probably get away with something under 200w pretty easy. Intel and AMD both have some pretty nice low wattage CPUs so its really a matter of preference. Several companies have a nice selection of SFF cases, but they are a bit more pricey then your standard fare. Keep in mind those are peak values, the system will use considerably less when it is just idling away.

    Monday, June 18, 2007 2:11 PM
  • Here is a good article that actually covers some of your questions.




    With the new AMD low power processors, Tom's Hardware was able to build a system that idles at about 50W and uses about 90W under load.

    Monday, June 18, 2007 2:44 PM
  • Using old hardware helps too - I have a Pentium III 550mhz machine that I'm using for WHS.  I don't have any performance issues with it, and it's using about 60 watts idle.


    Monday, June 18, 2007 3:37 PM
  • Using a standard pc  whiteout screen and using a build in low end vga controller , Three hard drives . I am running around 70 watt. ( p.s. my power supply is 650 Watt , but you are never using it to the maximum)

    greetings from Greece
    Monday, June 18, 2007 3:38 PM
  • My WHS runs about 36W idle, but I used parts specifically for low power where I could.

    • Antec Earthwatts 380W power supply (80+% efficient)
    • Via C3 1300+ on Syntax motherboard with onboard video
    • 512 MB DDR
    • Hitachi 400GB T7K500 with advanced power management enabled for low rpm idle
    • Maxtor 320GB
    • Sony DVD+/-RW optical drive (plugged in but never running)
    When I replaced the original Antec SmartPower PS with the Earthwatts, it dropped the idle power from about 45 watts to 36 watts.
    Tuesday, June 19, 2007 3:08 AM
  •  stevex wrote:

    Using old hardware helps too - I have a Pentium III 550mhz machine that I'm using for WHS.  I don't have any performance issues with it, and it's using about 60 watts idle.



    I have an old pc in the loft with a similar specification to the one you are using. I'll give that a try and see what sort of power it consumes.




    Wednesday, June 20, 2007 1:47 PM
  • Actually, using old hardware is the worst way to reduce power consumption...  Due to circuit/trace aging, it's not as efficient at the micro level, and older processors drew more power than the current dual core versions.  Plus, depending on how old the old processor is, it might not support the EIST/C1E systems that newer CPUs do.  These systems allow the CPU to throttle down to a "lower power state" when idle.


    The greatest influencing factor in power draw is the number of HDDs in the system.  If you use a newer CPU (a notebook motherboard/CPU would be the best as they have the lowest draw of all), turn on EIST, turn off all unneeded ports on the motherboard, and set up WHS for drive spin down when idle (and might want to try Sleep/Wake on LAN), I'd bet you could keep the system well under 70w of consumption at peak, and probably under 30w when idle...

    Wednesday, June 20, 2007 2:19 PM
  • very interesting results!
    what did you use to measure the consumption?
    I'm afraid my old power supply is rather a sucker...  I'd like to check that out.

    Thursday, August 2, 2007 9:17 PM
  • When looking at building a computer to run WHS without high power requirements there are a few things you may want to consider.

    Over the last few years there has been a effort by a number of large companies to reduce the power consumption of servers, one of the prime targets that has been reviewed is Power SUpply efficency. Many older and some current PSUs on the market will loose near half the electricity draw in conversion, in extreme cases you could see a 500w PSU using 250w simply to convert from AC to DC. Thankfully there are many good PSUs on the market today that will provide a conversion factor of 80% or better, and when it comes to PSUs you generally get what you pay for.

    When considering to build a headless server from desktop parts one way to dramatically reduce power draw is by using onboard graphics, another option is to put a video card in your server only during installation and remove it later on.

    The next largest concern for power draw is the cpu being used as many older cpu's have larger power envelopes than the newer 65w-35w models. If you can, desiging a system around the use of a slower cpu will reduce the power consumption especially if you are not doing and computentionaly intensive tasks on the machine.

    With the addition of storage you also will need to look at the expected draw from each hard drive, thankfully large hard drives typically have a operational average draw of ~13w http://www.seagate.com/docs/pdf/datasheet/disc/ds_barracuda_7200_10.pdf

    As a result, it is very likely that you can build a computer for use by WHS within a very small power envelope. As such in most cases using a 250w efficent PSU will likely fill all your needs.

    Thursday, August 2, 2007 10:13 PM
  • Have a look at the C7 VIA chip sets used in the mini-itx range of motherboards.

    I'm running one at less than 35W with 400Gb drive and DVD and no fan.  Tranquil are looking to make the new boxes WHS ready according to this thread their TGV7 uses as little as 23W...


    Saturday, August 4, 2007 11:36 PM

    Well it's here - the preview !




    we now plan to go down to < 16W - prior to shipping next month




    Monday, August 6, 2007 9:56 PM
  • I've used an Asus Terminator 1 barebones since WHS beta 2. it has a Via C3 (800 Mhz) cpu. the power supply is 165w. if you enable Q-Fan in the bios it will regulate the ps fan speed depending on cpu temperature. I typically register 38-42 watts at idle in this configuration. my set-up has one 320Gb Seagate PATA drive, one 160 Gb Seagate SATA drive and 512 Mb Ram. I also have a DVD attached but only use during OS install. The set-up works fine for me -- file server and file backup. I don't use it for streaming media -- if I did, I would have a more robust system than the C3.


    I'm using  a Kill-A-Watt to measure power usage. you can get one at





    Thursday, August 9, 2007 2:28 AM
  • Looks good, but I though 1Gb Ethernet was one of the design requirements that the WHS team had put forth to the OEMs.

    EDIT:  Oops.  This post was intended as a reply to Tranquil PC.  Somehow the quoting didn't work.
    Friday, August 10, 2007 2:53 PM



    After reviewing the web 'WHS requirements' and the 'OEM (V1 July 2007) document' there is no reference to Gbe LAN, as mandatory - it is true, that is a recommendation, but 10/100 is the base line.

    Please check out the PC Pro preview, they publically commented on what we have also done - streamed multiple 720p HD TV streams, and MP3 music files - and monitored the network connection - there are no problems.


    If we are to expect problems with networking / streaming, we expect these to be due to a) use of WiFi (not ideal for HDTV if the signal is anything other than very strong), and b) use of multiple low cost (un managed) switches which can occasionally cause networking problems, if subjected to high traffic demand.


    Our general attitude to development, is keep it simple - if there is no need for a Ferrari (of the PC world), and a Corsa will do - then use a Corsa, or perhaps one a few steps up.  But the top of the range (CPU/LAN etc) device will only use additional power, and create unwanted acoustic intrusion.  Keeping it 'fit for use' will result is substantial operational cost savings (approx £20-50/annum), reduced 'green' damage, and extended operational life time (no fans) - not to mention the acoustic benefits for the home.


    If you are looking to build a unit - think about what is 'needed' - not what the marketing depts tell us we 'must have'.



    Sunday, August 12, 2007 8:42 AM
  • They must have changed the requirements then, because at WinHEC 2007, Charlie Kindel's charts show the minimum requirements to be 1.2GHz X86, 80GB internal HDD with tool-less expansion, 512MB RAM, GbE, 4 USB expansion ports, and max 30dB acoustic emission.  Not allowed were:  wireless network adapter, video connector, optical drive, keyboard and mouse ports, and RS232 and parallel ports.  I'm not trying to be critical but just to communicate what I saw and heard at WinHEC earlier this year. 
    Sunday, August 12, 2007 8:15 PM
  •  shutrbug wrote:
    • Hitachi 400GB T7K500 with advanced power management enabled for low rpm idle

    How did you configure that?

    Sunday, August 12, 2007 8:58 PM
  • I used the Hitachi Feature Tool available here.  There's an option for configuring advanced power management there and you just drag the slider back and forth.  I made a boot CD from the CD image available on that site.  Nexsan uses these advanced power management features in their SATAbeast products to get really low power usage in their storage products.
    Monday, August 13, 2007 2:06 AM

    Here is a Power Consumption calculator:  http://web.aanet.com.au/SnooP/psucalc.php

    If you cannot reach it, try: http://www.extreme.outervision.com/psucalculator.jsp



    1) Each HD consume around 8w idle and 12-15w when active.

    2) Intel and AMD CPUs generally consume 60-90w loaded.  There are energy efficent versions which consume 35-50w loaded.  For a home server, it is unlikely they will ever be under full load.  Typically, you can expect the processors to utilize less than half the power when idle.

    3) The chipset utilizes around 20-50w

    4) Each case fan uses 2-6w

    5) Each GB of RAM uses 10-15w



    To guesstimate cost of running the server:

    Wi = power consumption of the system idle

    Wl = power consumption of the system loaded

    Ti = time the system is idle a day

    Tl = time the system is loaded a day

    C = rate of a killowatt-hr by the eletrical company


    ((Wi/1000 * Ti) + (Wl/1000 * Tl)) * C = Cost of Running the server for a day.
    Tuesday, August 14, 2007 3:03 PM