Buy one of these and have it in for 1hr of normal use, 1hr sleep, 1hr power off.
UK Power Meter Energy Monitor Plug-in KWH Electricity Meter UK stock 3-5 days | eBay
We're having a big push on power usage here and I've been asked to investigate our PC's and Printers and see if we can reduce it any.
Probably a stupid question but I haven't got anything to work it out with at the moment, but any rough guidance on how big a power difference is between a PC which has gone to sleep and a PC which is switched off?
Also, and I can't see how but I'm going to make myself look stupid and ask, is there any easy way to determine whether a PC is switched off or on standby without going round and trying to wake up each individual PC?
Any help/guidance is appreciated.
Sleep can be broken into various ACPI "Sleep" States,
Look at the "global states"
Advanced Configuration and Power Interface - Wikipedia, the free encyclopedia
the main difference is between soft off and mechanical off.
I did a blog post about power usage a while back - How much power does a PC use? | my world of IT (video included).
Found our old Pentium 4s were 100W+ while idle! Newer AMD E-350 PCs with SSDs were just 16-20W.
Get one of the power meters though - can use it with anything and provides a real view of the impact of power consumption.
Thanks for the replies, guess I'll have to go arround for a day and just work out what the differences are.
Your blog post @jamesfed was actually quite interesting though, I might be using it with another push for newer machines.
No problem at all and glad it helped!
Even when a pc is shut down and turned off it will still use standby power, between 1 and 4 watts. Older pc's are worse. I think I think this depends on the motherboard.
Sleep will normally use about 6 or 7 watts.
On a side note anyone looking to save power at home. I can recommend this product.
Last edited by techsup1983; 18th January 2013 at 11:26 PM.
I have found that sleep uses very little power and is almost the same as shutting down or hibernating (but more convenient when turning on again). Switching off at the wall uses less but then you can't use Wake on LAN to start the computers for updates or remote access. It's also a pain unless you have a breaker for the whole ring main in the room.
Powered on energy consumption varies a lot depending on the hardware (and CPU activity) so you would have to measure this. Either with a plug in meter or with a clamp meter on the whole circuit (but this is less accurate as it only measures current not voltage). You might be interested in this project I knocked up Raspberry Pi Electricity Monitor | UnOp as it can be used for measuring and to teach kids about power consumption.
As far as monitoring which computers are on, I've recently launched (still in beta) a service to do this at Shutdown Scanner (beta) and it's free to use. You just need to install the probe software on a single machine on the network and it makes nice interactive web-based graphs of when the computers are on in real-time.
Danp (24th May 2013)
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