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how much power do pcs use?

Discussion in 'General Hardware' started by elite, 3 Mar 2006.

  1. elite

    Wise Guy

    Joined: 22 Jul 2004

    Posts: 1,237

    Location: North East, Cleveland

    mam just got the electric bill in for £240, said it was alot higher then last months, she now thinks its my pc and my brothers, do pcs really use alot of power or is there any way i prove or show her somthing on how much they use?

    i dont leave my pc on over night, nor does my brother
  2. phill


    Joined: 25 Nov 2005

    Posts: 419

    am i right in assuming if you have a 300w PSU thats the same as having three 100w light bulbs on?, or is that complete bs ? :{
  3. deano

    Wise Guy

    Joined: 18 Oct 2002

    Posts: 2,261

    Location: Kidderminster

    A 300w psu will not be running flat out / using its full 300w's when it's on, so i think you a re a little of the mark with your statement, but there again i could be wrong :eek:

  4. vanandjuanunited


    Joined: 20 Oct 2005

    Posts: 5,622

    Its your dual core!!!!!!!! :D

    You can buy plug in thingies (technical term) that will tell you how much power is being consumed.
  5. Bri


    Joined: 19 Oct 2003

    Posts: 4,839

    Location: Sunny Teesside

    Check for estimated readings on your previous statements, that's the most likely cause of an unexpectedly large bill.

    I run my PC 24/7, live in a 3-bed semi with the wife & use about £30 per month electricity.
  6. Kaed


    Joined: 17 Jan 2005

    Posts: 735

    Location: Lincoln

    Running my pc, monitor, cable modem, network switch, subwoofer and speakers, tv, dvd player, video, alarm clock and bedside light off a ups doesn't seem to upset things at all.

    Unplug everything, plug one of those electric heaters in, set it to the lowest setting possible and turn it on, and my ups flips out and goes nuts.

    Bri's suggestion sounds most likeliest (sp?)
  7. dirtydog


    Joined: 18 Oct 2002

    Posts: 47,398

    Location: Essex

    No way is that down to PC usage! :) Point your mum (mam? :p) at this thread so she can reassure herself.
  8. Deka


    Joined: 15 Jun 2004

    Posts: 96

    Yeah, you can buy a plug that goes into the power socket with an LCD display on it, and it will give statistics on whatever is plugged into it, such as KW/h (kilowatts per hour) iirc you can also include the cost of elecricity and it calculates how much the device is costing to run.

    I've wondered about this too, I used to get moaned at a lot about high electricity costs.
  9. eztiger


    Joined: 22 Sep 2005

    Posts: 66

    Completely unscientific test, but get her to watch the electricity meter spinning. Then switch all your stuff off and ask her if she's noticed a difference.

    Chances are she will notice a difference, but not the drastic one she was expecting..and the thing will still be flying round.

    I've been through this before with my parents and, more recently, with a flatmate (turned out it was the electric water heater being on almost constantly due to us mucking up the settings).

    It depends on the PSU you have in your PC. Whatever wattage rating it is is pretty much the maximum it will dish out (and even that assumes 100% efficiency which is pretty much unheard of). As has been pointed out though your PC will rarely be hoovering power for its components all the time.

    I think the days of comparing it to leaving light bulbs on are on the way out (with your dual sli machines and multi core cpu's all wanting 400w+) but I'm pretty confident they're still among the smaller power drains in your average house.

  10. MadMan-JaMeS


    Joined: 15 Mar 2004

    Posts: 3,071

    Location: Oxford

    i think not long ago someone worked it out to cost like 50p to run a pc and monitor 24/7 which isn't bad but i cnt remember wht wattage PSU he had :S
  11. Rotty


    Joined: 18 Oct 2002

    Posts: 41,006

    Location: Notts

    not sure who you are with but many electricity companis have recently had huge prices rises southern/scottish/atlantic havehad a rise of around 20% recently and powergen and britisg gas have one imminent
  12. woodsy2k

    Wise Guy

    Joined: 6 Nov 2005

    Posts: 1,547

    It depends on how active your core(s) are. As the cpu is the single component in the PC that uses the most power compared to anything else, If your core(s) are on 100% 24/7 then you might use a fair bit of electricity. However dont think that just because a pc is idle, it wont use hardly any power at all, because that is rubbish. Hard disks, cd roms, ram, fans, motherboard all that other stuff uses alot of power when combined.

    In answer to someones post about PSU wattage, The pus is never 100% efficient, infact apart from the seasonic ones, most are around 60 - 75% efficient. So that means that even on full load, you still are only using your PSU's rated power output, with a percentage loss due to efficiency.

    With that in mind, having a more efficient PSU could slightly lower the cost to run the same PC.
  13. VeNT


    Joined: 9 Jan 2003

    Posts: 20,694

    Location: Cornwall

    mums A64 3500/1gig ram, x700, 2 hard drives, 2 DVD drives takes about 250W max (this is actual readings rather than working it out, as shes got a 500W PSU)
  14. Dutch Guy


    Joined: 18 Oct 2002

    Posts: 24,563

    Location: Amsterdam,The Netherlands

    A fairly good spec machine will use ~250W at full load excluding a monitor which is ~50W for a TFT.

    A Idling this is much less and might even be below 100W

    So if it is on about 8 hours a day it is 300W*8 = 2.4kWh a day times two computers is ~5kWh
    say it is 10p/kWh that means it costs 1 quid to run the two computer one day or 30 quid each month

    This figure can be a bit higher if you run the computer longer than 8 hours or when you have a CRT monitor that is on all the time.
  15. Deka


    Joined: 15 Jun 2004

    Posts: 96

    Completely OT, but what is that car in your sig Dutch Guy?
  16. Raikiri


    Joined: 5 Jul 2005

    Posts: 17,774

    Location: Brighton

    I think it is a Bugatti Veyron 16/4 :p

    As said it will only be using about 100w idle and at max 250 load.
  17. Dutch Guy


    Joined: 18 Oct 2002

    Posts: 24,563

    Location: Amsterdam,The Netherlands

    Bugatti Veyron, but it's not mine though as I did not have 700k lying around :p
  18. Deka


    Joined: 15 Jun 2004

    Posts: 96

    Cool, Thanks!
  19. PeterNem


    Joined: 15 Feb 2003

    Posts: 8,322

    Location: NJ/NY, USA

    If your PC needs say 250 watts at full load and your PSU is say 70% efficient, you need to remember to multiply 250 by (1/0.7).