I'm turning a workstation into a internal mediawiki webserver for my small business (limited budget and too many workstations). The workstation has both a CD and floppy drive, neither of which are needed at all. Is there any measurable power saved in removing the drives as opposed to just letting them sit there idle all the time?


Yes, the difference is measurable, although whether it's significant depends on how much you pay for power. To work it out (assuming that you electric utility bills in kilowatt-hours, or kWh):

  1. Look up the specs for your drives online, and look for a "quiescent power draw" figure, or something similar (should be fairly obvious which one it is), the figure should be in Watts (W)
  2. Divide 1000 by this number, to get the number of hours it takes for the drive to consume 1kWh of electricity.
  3. Divide the number of hours in a month (I use 730.5 as my standard number) by the previous number, to get how many kWh of electricity the drive draws each month.
  4. Look on your electricity statement for how much a kWh of electricity costs you, and multiply that by the previous number to get (roughly) how much it costs you to run that one drive unused for a month.

I say "roughly" because there's further power losses in your power supply and such that'll cost more electricity, but they're (hopefully) really not significant.


There is measurable (in KWh ) power saved. However I am almost convinced that what you are really asking is if you can measure this savings in cold hard cash. The short answer is no.

Story alert! From 2004 to 2006, I was running 4-6 machines, 24/7 In August of 2006 I added another 7 machines that stay on 24/7 as well.

My electric bill shoots to the moon when it's hot and running the A/C. I compared my monthly charges from 2004 to end of 2008 with the average monthly temperature and they correlate very nicely. Normal temperature: bills where similar before and after the added machines Cold - same as above HOT - you cry when you see the bill in 2004 or 2008 :)

The botom line is, you'll save more money by sweating and making your own coffee (ie avoiding Starbucks) than disconnecting CDrom drives.

just my 0.02 kWh :)


For devices such as CD and floppy drive the majority of their power consumption is caused by the motors. When those motors are not turning the consumption is negligible, as the electronics use very little power indeed. Still, if they're not necessary there is no reason not to unplug them.


Sampling a random CD-ROM drive in the old junk box shows that it's rated at 29W. Even if it ran all the time, it wouldn't amount to much. I'm guessing that the power draw while idle would be negligible.

EDIT: Worst case scenario example for my $0.08/kWh, my CD drive running at its fully-rated power draw of 29W would amount to $20.32/year or about $1.69/month.

  • 1
    I'd pay the $1.69 a month to save the the time it would take to reinstall it and reboot to detect it the one random time it's needed. – MDMarra Aug 8 '09 at 22:35
  • @MarkM: There is that -- although I've never once used the DVD-RAM drive that came in my current laptop (bought about 18 months ago), and the netbook I got about 3 months ago hasn't needed a CD-ROM anywhere either. PXE netboot for the OS install and network for everything else, too... – womble Aug 9 '09 at 4:15

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