Computer Power Use

This table shows the power consumption of some of the computers I own. I use a domestic electricity meter that was certified for use in billing customers to measure this. Any inaccuracies in the measurement will
correspond to inaccuracies in electricity bills of people who use such computers.

Before anyone asks, I am not interested in contributions of data, I believe that doing tests with a different meter or in a different country with a different supply voltage will diminish the accuracy of the results. Also I will provide minimal analysis on this page (the numbers should allow you to perform your own analysis).

Before I started such tests I had significant problems cooling my house in summer. Based on the results of these tests I made changes such as replacing the Compaq 1GHz Athlon machine by an IBM 1GHz P3 machine for a small server I run, this saved 49W of power, 49W of power which mostly ends up as heat makes a significant difference in a small server room when running 24*7!

All the machines below apart from the SMP machine are workstation class machines, they don’t have ECC RAM and their PSUs are designed for small load. The SMP machine has a PSU designed for a desktop machine (I couldn’t easily obtain any other type). If it had a PSU designed for server use it would draw more power.

Unless otherwise noted all machines were idling while running Linux (idling while running DOS uses significantly more power).

The summary of this table is, P3 is a great CPU for power to computer power ratio, the P4 isn’t too good, and the Athlon sucks badly – don’t run an Athlon server if you have heat problems!

Thinkpad T20 500MHz P3 512M 30G IDE 10.7W
Cobalt Qube AMD K6-450MHz, 128M RAM, 10G IDE 20W
Thinkpad T41p 1.7GHz idle at 600MHz, screen on and battery charged 23W
Compaq SFF 800MHz P3 512M 10G IDE spun-down 28W
Compaq SFF 800MHz P3 512M 10G IDE 35W
Compaq 800MHz P3 128M 10G IDE 38W
IBM 1GHz P3 256M 30G IDE, idling 38W
HP Pavilion 513A Celeron 1.8GHz, 384M RAM, 40G IDE 45W
HP Pavilion 513A Celeron 1.8GHz, 768M RAM, 2*80G IDE + 46G IDE 58W
Compaq 1.1GHz Celeron 512M 40G IDE idling 46W
HP/Compaq Celeron 2.4GHz, 512M RAM, no hard disk 43W
HP/Compaq Celeron 2.4GHz, 512M RAM, 300G IDE 50W
NEC Pentium-E2160 1.8GHz, 1G RAM (1 DIMM), 160G S-ATA 52W
Packard-Bell (NEC) Celeron-D 2.93GHz, 512M RAM, 2*20G IDE 75W
Compaq 1.5GHz P4 256M 20G IDE, idling 78W
Compaq 1.5GHz P4 256M 20G IDE, installing 85W
SMP 2*P3 1GHz, 1GB RAM, 2*U160 SCSI 18G disks idle 81W
SMP 2*P3 1GHz, 1GB RAM, 2*U160 SCSI 18G disks disk busy 99W
SMP 2*P3 1GHz, 1GB RAM, 2*U160 SCSI 18G disks CPU busy 130W
SMP 2*P3 1GHz, 1GB RAM, 2*U160 SCSI 18G disks CPU and disk busy 136W
Compaq 1GHz Athlon 256M 20G IDE idling 87W
NEC Pentium-D (920) 2.8GHz, 1G RAM, 160G S-ATA 98W
White-box Athlon XP 1700+, 768M RAM, 2*80G IDE + 46G IDE 110W

Here is the Computer Related Power Use page [1] (for switches, filters, and other things).

2 comments to Computer Power Use

  • David Aitken

    Hello Russell,

    I have just started doing some similar measurements using one of those plug meters (MS6115), and have noticed that even if the computer is turned off it still draws 7 watts of power (this is using both a Compaq and my home no-name PC).

    The implication is that the PC needs to be turned off at the mains to minimise power consumption.

    Have you observed anything of this nature?

    David Aitken

  • This is a nice collection of information – the best rating I’ve seen is the PC Engines ALIX – 5 watts of power. A little slow when trying to use X11. One step up from there is the VIA C7.

    I’m grappling with hard drives now – especially a RAID 5 system.

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