I read an article which tells power consumption by many devices. It say that a desktop computer (computer and monitor) use 400 to 600 watt.
While when i checked my computer and monitor with meter, it was about 60 + 60 = 120 watt (computer + 17" CRT monitor) after loading windows xp and running an application. The voltage is 220V here.
Which one is correct? How much power does it consume?


closed as off topic by Mark Eichenlaub, David Z Jan 6 '11 at 22:39

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  • 1
    $\begingroup$ Where is the physics in this question? $\endgroup$ – Mark Eichenlaub Jan 6 '11 at 10:29
  • $\begingroup$ I agree, this question doesn't belong here... $\endgroup$ – PearsonArtPhoto Jan 6 '11 at 13:58
  • $\begingroup$ I asked it here to electronics.stackexchange.com/questions/8647/… Where else does it belong? (Although i got me answer there somewhat) $\endgroup$ – SMUsamaShah Jan 6 '11 at 17:58
  • $\begingroup$ try Super User. In fact I would bet this question has been asked there already, and probably answered with "it depends on what's in your computer." $\endgroup$ – David Z Jan 6 '11 at 22:39

I sincerely doubt that a computer could use 400+W under normal circumstances. That is the typical power rating of the transformer powering the computer. So, at peak the computer could use that much power.

This peak consumption in practice means something like:

  • CPU fully loaded
  • GPU fully loaded
  • Hard disk at maximum throughput
  • All the USB and Firewire ports supporting powered devices
  • Wi-Fi and Bluetooth turned on and trasmitting

Also, IBM compatible motherboards and power transformers are made to support different hardware configurations. Examples:

  • Some motherboards support multiple CPUs
  • All support many hard drives
  • etc...

You can think of it this way as well. Servers normally have two PSUs (for redundancy). Both are plugged in at the same time and both could theoretically support the server by themselves. So if the maximum peak wattage of the server is 500W, you would have 2 500W PSUs plugged in at the same time. However, the consumption of the server will not exceed 500W.


I have a dual socket 8core system on my desk right now, with dual moniters. In near idle mode, with monitiers swicthed off it draws 200watts (measured), even with moniters on (30-40watts apiece), and 8 CPUs pounding away it is only about 360. Most systems are a lot less beefy than that. Some of the hi performance graphics cards may be pretty hungry however. For about $20 you can buy a Kill-a-Watt meter and measure such things yourself.


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