PC Power Consumption

How much power does your PC Consume?

Much discussion has been generated as a result of the August 14th 2003 power failure, and subsequent requests to conserve power, as to how much power a PC workstation or server consumes. The main question being asked is whether-or-not it is better to power it off at night-time. In response IST has does tests and would like to present the following  pros and cons relating to powering off your PC.


According to tests conducted by IST, Hardware Support, tests showed the following. On a Pentium 4, 1.7GH machine:

The monitor consumption was not included in these tests. Also, number will vary depending on the processor you have and what other peripherals you may have connected.


This means that each PC consumes roughly the same amount of energy at it’s highest usage level as a 100w light bulb.


A Sony 17” monitor, by far our most common, consumed 75w when in use. When power-saver mode kicks in (and the monitor goes black with a yellow indicator light) the power consumption is negligible to the point that our test equipment did not even register any power use.


The total power consumption of a typical PC and monitor does not consume more than 175 Watts of energy at its highest rate. At night time when your PC is “sleeping” it only consumes 35 Watts.


As mentioned power consumption varies depending on hardware. There is a PC Power Consumption Calculator available online at:

            http://www.distortionwave.com/power.html if you wish more details.     


The bottom line is you would conserve more energy by shutting off one 40 Watt overhead florescent light bulb than your PC at night time.

To power off or not?


There are several factors at play here. They include the following:


According to the Daily Bulletin on Monday August 18th, “On a typical workday, UW is using about 13 megawatts of power”. According to Dennis Huber (vice-president administration and finance), is quoted in this same bulletin as saying: “The "base load", or minimum consumption, is about 4.5 megawatts”. This means if the 1000 Academic Support department PC’s that IST administers were all left on overnight they would only consume 35 kilowatts or ¾ of 1% of total load.


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Created by: Manfred Grisebach, IST – Systems, August 20th  , 2003