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How much electricity does a computer use

By Edited Sep 13, 2016 0 2

Thermaltake PSU

The power supply is one of the crucial elements that make up the wonder we call the personal computer. With its status as a crucial element, why then do we often overlook the PSU?

One valid answer is that the PSU is often included when purchasing a PC chassis. Another possibility is that we do not know how much power the individual components require. In this article I intend to clarify the latter.

The motherboard (20 to 60 watt)

In today’s market we are spoiled for choice when purchasing motherboards. The entry-level desktop motherboard consumes as little as 20 watts, add a couple of extra USB ports and the consumption could climb to 35 watts. When purchasing a gaming motherboard with multiple PCIe slots the need tops at 60 watt.

The processor (60 to 140 watt)

With the introduction of the new multi core processors from Intel and AMD, power consumption peaks at 140 watt. In the table below I have listed some popular processor choices with the power requirements of each.





Core2Duo 8 series

65 watts

Athlon II X2

65 watts

 Core2 Duo 9 series

95 watts

Athlon II X3

45 watts

Core2 Quad

95 watts

Athlon II X4

95 watts

Core i3

75 watts

Phenom II X2

80 watts

Core i5

95 watts

Phenom II X3

95 watts

Core i7

130 watt

Phenom II X6

140 watts






 RAM (3 to 6 watt per Dimm)

PC’s use three different types of RAM; they are DDR, DDR2 and DDR3. DRR still requires the most with 6 watts followed by DDR2 with 4 watts and lastly DDR3 requiring a mere 3 watts per Dimm.

Graphics Card (50 to 300 watt)

The graphics card is often considered the most power-hungry part and to deduce its consumption level we will have to take a closer look at the power connectors present on the device.

Below is a guideline about what you can expect:

  • PCIe with no separate connectors 75 watts
  • PCIe with one 6Pin connector 150 watts
  • PCIe with 2x 6Pin connectors/ PCIe with a 8Pin connector 225 watts
  • PCIe with a 8Pin and 6Pin connector 300 watts

Miscellaneous components   (Find breakdown below)

Just add these components below up to tally your watt usage:

  • Case Fan 5 watts
  • Optical Drive 10 watts
  • Hard Drive 10 to 15 watts
  • Lighting (Refer to ballast)


When purchasing a new PSU make sure to leave some tolerance for expansion.

That concludes your PC's power consumption breakdown.







Apr 15, 2011 10:34pm
Does the 2nd generation i7 use the same amount of power as the 1st generation?
Apr 17, 2011 4:44am
The comsumption listed is for the 9xx series i7 the 8xx series uses a tad less around 95 watts.
Oct 18, 2011 1:10pm
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