While this isn't particularly Linux related it is PC related and I'd guess some people here may be knowledgeable in this area.
I'm trying to cut down my PCs' power consumption, one way has been to offload 'server' functions from my desktop machine to a much lower power server machine. That's now done and I'm looking at other ways to reduce power consumption.
I've been looking at the power consumption of my desktop machine and noticed that when in standby it consumes about 20 watts. So I checked how much it consumed when powered down completely (but still conencted) and it *still* consumed 20 watts. I.e. the power supply and motherboard even when completely idle take 20 watts. I suspect that this is mostly power supply losses.
When powered up, even though it's quite a fast machine (quad core processor, 8Gb of memory, two big disk drives) it only takes 50 watts so the power supply isn't all that inefficient when it's working.
So how can I search for power supplies that don't take much power when completely idle? Typical 'efficient' 300 watt and 400 watt power supplies are better than 80% efficient but that means they may well still consume 20 watts when doing nothing. Efficiency *doesn't* necessarily equate to low 'off' power.