How much power do a PC and monitor need?

Foad Adnani September 2, 2012

How many Watts or kW do PC and monitor need to turn on?

And if I work with my PC for 24 hours, how much power can use in 1 week?

  1. Dimal Chandrasiri
    September 12, 2012 at 4:55 pm

    it depends on the workload you put on your pc and the hardware components that are inside the pc. it may vary from like 200watts to 500-600watts. ( with modern day rigs. ) and as for monitors LED/LCD use lot less wattage compared to CRT monitors. if you are using a CRT, try to off it when ever you dnt need it! and for the pc, no one can give a certain answer. bt you can calculate the rough theoretical wattage by some websites. just search PSU calculator!

  2. Muhammad Ahmad
    September 5, 2012 at 3:57 pm

    Is there any software or application to check that how much electricity (number of watts) a computer is using.

    • HLJonnalagadda
      September 21, 2012 at 11:52 am

      Usually comes bundled with the power unit. Mine gives me a lot of choices to tweak, as well.

  3. susendeep dutta
    September 3, 2012 at 8:21 am

    Visit the link below -

    Although,this site is for calculating approximate wattage of PSU that your system needs to power on,it'll be useful to know how much power it'll draw.

  4. illegal3alien
    September 3, 2012 at 1:51 am

    Generically speaking, a LCD monitor takes around 40-50 watts. The tower will take around 100-200 idle and could easily spike up to 700+ depending on what type of computer you have. For a standard desktop, you'll probably reach about 300-400 watts max when you have the CPU fully utilized.

    We'll estimate 200 watts on average. 200*24 hrs*7 days = 33600 watt hours per week or 33kWh

    You can get a Kill-A-Watt power meter for $15-20 online and that'll tell you exactly how much power your setup is consuming. They are definitely worth the money if you want to figure out how much power your devices are using.

    • illegal3alien
      September 3, 2012 at 1:58 am

      For comparison, a Pentium 4 w/ a 16" CRT idles at 120-200 watts (based on Kill-A-Watt readings)

      My setup with a i7 920, a 22" LCD, and a AMD Athlon x2 CPU with both computers at 5-15% utilization hooked up to a UPS pull 400 watts. That means that the UPS is losing power, plus each computer's power supply will be losing power since we're converting back and forth to AC/DC and these are 60-80% efficient. If memory serves, the i7 is about 200 watts, the AMD 150 watts, and the monitor 50 watts.

      If you provide your setup, I'll see if there's a similar computer setup I can get a hold of and I'll test how much power it's consuming.

  5. Lambvolution
    September 3, 2012 at 12:44 am

    depending on hardware in your PC..if you have high end GPU Card, a lot of hard drive, overclocked processor, it can be 300watt or higher

  6. Rob Hindle
    September 2, 2012 at 10:56 pm

    As others have said the answer is "it depends...".
    You can get a device to give an instant fairly accurate rating for an individual device plugged into it like this (there are other makes and suppliers) but even that is only a guide figure. The PC will use more power when it's handling some tasks than others and, since you mentioned leaving the PC on for 24 hours, then some components may go into power-save mode for some of the time.

    The device Maplin sell can give a cumulative figure so plug a multi-socket extension into the monitor and plug your PC and accessories (e.g. monitor, printer) into that and get the cumulative reading over a week.

    • Rob Hindle
      September 2, 2012 at 11:05 pm

      oops, reading my response back I used "monitor" to mean two different things, the power consumption monitor and as a name for the computer screen. Apologies to anyone who got confused!

  7. Usman Mubashir
    September 2, 2012 at 10:55 pm

    an old monitor can eat upto 150 watts of electricity per hour,
    newer monitors need less energy per hour ~70 watt/hour
    you can check your monitor, or its box for power ratings.

  8. Mike
    September 2, 2012 at 7:46 pm

    There are systems that use less than 50 Watts (e.g. ULV CPU and IGP) and there are systems that use up to 1000 Watts (e.g. Quad-GPU).

    Without any details the best answer one can give is that it requires up to the maximum wattage of your power supply plus monitor plus losses in efficiency.

    The power supply wattage and efficiency should be stated on it's side. As for the monitor one would have to look up it's specification but usually it is 80-100W for a CRT, 30-60W for a TFT.

    As for the consumption over time the term "work" has to be specified. Even if you have high-end components when your "work" is restricted to Office applications and internet usage the power consumption is usually low. On high CPU and GPU usage this number will probably triple or quadruple.

  9. Kannon Y
    September 2, 2012 at 5:13 pm

    According to this article the average computer uses about 270 watts. That's including the monitor. However, if you undersupply power, such as use a uninterruptable power supply with a lower power supply than required by your system at max draw, you will experience all kinds of computer glitchiness, BSODs, black screen crashes, etc...

    So even if you undersupply power, the computer MAY still turn on, but it will behave erratically and its operation and performance will be unstable.

    Other contributing factors to a computer receiving less wattage than required is a decaying power strip. The internal components (capacitors) break down over time and, as they decay, provide less wattage. Eventually your computer may experience the symptoms of power undersupply. Some technicians advocate changing the power strip every few years or so. I don't, though - that's just a waste of money and materials.

    The biggest contributing factors to power consumption are the efficiency of your power supply and its total wattage. If you have a 70% efficiency CPU, and a 300 watt PSU, the total draw on your wall socket, at max, would be 390 watts. If I did the maths right. :-)

  10. ha14
    September 2, 2012 at 4:43 pm

    depends on hardware and monitor, for instance LED monitor ask less power

  11. 7e1593f85fa133f4d3a9c11ea5dfb791
    September 2, 2012 at 4:41 pm

    Each computer is different and has its own different power usage. You can find out by googling your PC model and thendo the mathforhow much it uses. Or you can head to the store/EBay and buy a little outlet device that reads how much electricity your device is using at the time.

  12. Bruce Epper
    September 2, 2012 at 4:08 pm

    Your question is far to generic to support any kind of answer. The power consumption of any device depends on the characteristics of each specific device. Give and exact make and model of the monitor and all of the components of the PC and a fairly precise answer can be calculated. Without any of that what you are asking is more like "what is the volume of the cardboard box I have in front of me?".

  13. GrrGrrr
    September 2, 2012 at 4:07 pm

    Read the link below:
    How much electricity do computers use?

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