How green is my PC?

Posted on 16 Jan 2009 at 15:58

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Watts up

Laptop users should be familiar with Windows' power saving settings, which help eke out more computing time from each battery charge. What's often overlooked is that desktop users can also implement power saving to reduce the amount of mains electricity they consume.

While you're working on your PC, its energy usage will rise and fall according to how much processing it's doing, but it's essentially using power all the time. As soon as you stop working, it makes sense for it to reduce its consumption by closing down as many components as possible until you come back. In general, the monitor and hard disk should be the first to go. The hard disk isn't needed all the time, so it can be turned off without causing much inconvenience, while the display, though obviously essential, can be reactivated instantly when required, so it may as well be turned off when the system is even briefly idle.

Perhaps surprisingly, your PC will use a couple of watts of power even when it's turned off. Note that for PCs, 'standby' means the same as 'off' - that's when you've shut the machine down completely and there are no LED lights showing. This is not to be confused this with 'sleep' mode, in which the system memory is still powered up, ready to continue from where you left off at the touch of a key. In sleep mode, the PC is likely to use about 3 to 5 watts, a tiny fraction of the full power load, so it's well worth ensuring your system spends as much time as possible in this state. On standby (switched off), most PCs will still use 1.5 to 2.5 watts, and some even more. By 2010, EU regulations require that new PCs should use no more than one watt while on standby.

The only way to stop your PC using any electricity at all is to switch off the socket. There's no harm in doing this, as long as you first shut down the PC or put it into hibernate mode. This is where the contents of memory are written to the hard disk, which doesn't need power to retain data. The easier it is to turn off the mains, the more likely you are to do it, so try to make your socket(s) accessible, rather than obscured by a rat's nest of power cables under your desk.

One option is to use a good quality multi-way extension with a single on/off switch, to kill your PC and peripherals all at once, or switches for individual plugs. Connect things like your answerphone to different sockets so they stay available when your computer kit is off. Or you can operate hidden sockets using one of the many remote control plug systems now available, where you install a small unit between the socket and mains plug and operate it from a key fob or switch panel.

Companies such as Bye Bye Standby are cannily marketing these gizmos as power saving tools. However, do keep in mind the difference between sleep and standby. If you cut the power to a PC while it's in sleep mode, it won't be able to start up again from the same point, you'll lose any unsaved data, and the unexpected shutdown could cause glitches with Windows. Make sure the system is either fully shut down or hibernated.

Yes you can

With so many options available to reduce the environmental impact and running costs of your PC, what are you waiting for? Get tweaking and start saving today.

Author: Adam Banks