Power consumption, switching on and off.

arc@css · 20 Oct 2009 at 19:07

Just a quick querie, is it more economical to leave your PC running if say, you're going to be away from it for only an hour or so? At the moment I tend to switch mine off several times during the day and was wondering if it was a false economy? It must take an initial surge of power to get it up and running and like with a car - switching the ignition on and off uses up fuel, so better to leave it running providing it isn't for too long. Just curious, perhaps my money saving afterthoughts are not worth it.

JonJ678 · 20 Oct 2009 at 19:16

Interesting question. I'm pretty sure the answer you want is hibernate/suspend, but I'd like to know if computers draw more power during boot than when idle.

Hard drives draw more wattage to spin up, but I'm not sure the rest of the machine would do. It's fairly different to a car really

Not the best person to reply though, mine doesn't get turned off

Angst · 20 Oct 2009 at 19:58

i saw this somewhere else before and they worked it out to be like the initial surge was the same as less than a few minutes of use, dont hold me to this though as they may have got their calculations wrong.

_SBradley_ · 20 Oct 2009 at 21:05

I have a power meter plugged in behind my PC, and I've watched it during startup. The current draw while Windows boots is about the same as when I'm burning a CD, and not much higher than idle.

I'd say, if you're going away from your PC for a very short while, leave it running (presumably there'll be some power management in action anyway). If you're going away for an hour or so, put it to sleep. (My PC uses just a few watts whilst sleeping.) If you're going away for a longer time, hibernate.

I'm not sure that hibernating and unhibernating is any more efficient than shutting down and restarting, but I only restart when necessary, just because it's quicker.

arc@css · 20 Oct 2009 at 23:02

Interesting points, thanks guys

TheVoice · 20 Oct 2009 at 23:30

I personally just use Sleep all the time. Means it starts up instantly, and uses barely any more power in sleep than a full shutdown anyway. Hibernate is a bit pointless on a PC that has a constant mains connection, it's really designed for notebooks (so as not to use any battery power).

weird_dave · 21 Oct 2009 at 11:57

I'd say leave it running, HD failures often happen at power up.
I've found hibernate is slower than just reloading everything you had running before shutdown, possibly due to loading in the entire contents of memory rather than just the portions that are actually in use.