Does shutting down and repowering CPU consume more energy?

Question

I have an internetshop that has 20 CPUs. Only 50% on average are being used throughout a regular day and almost 80-100% during saturdays. I use a Server-Client to Shutdown an unused computer but sometimes after 5-30 minute range it will be turned on again by another customer.

My questions is, will leaving an idle computer with monitor shutoff due to 5 minute idle left for 30 minutes or so be more wise than shutting a computer down and turning it on after 30 minutes.

I asked this because I though I read this before when I was a kid and I was told by mom to shutdown my Computer when we will eat for lunch or dinner and I stated that its more power consuming to shut it down and turn it on again. Atleast thats what I believed then.

Easy way to tell - buy one of those watt-meter plugs, run two CPU's on the two power-plans, measure which one uses more power. — John U, Jan 23 '13 at 10:31
I understand that HDD lives are significantly longer if continually powered. May or may not be true. — Russell McMahon, Jan 23 '13 at 11:02
It can depend on type - server HDD's are designed to run 24/7, "consumer" hdd's are designed with powering on/off in mind, although it's always going to wear the bearings faster. — John U, Jan 23 '13 at 12:04
Is it? Spinning wears on the bearings, too. And if the computer is on, it's probably accessing data, wearing the bearings in the arm. I'd like to see a reliable source for this claim. — Phil Frost, Jan 23 '13 at 13:13
Someone just asked the same question of lightbulbs, and even though computers and lightbulbs and computers are very different, the argument and conclusion is essentially identical. — Phil Frost, Jan 23 '13 at 16:30

score 3 · Answer 1 · answered Jan 23 '13 at 10:29

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My questions is, will leaving an idle computer with monitor shutoff due to 5 minute idle left for 30 minutes or so be more wise than shutting a computer down and turning it on after 30 minutes.

Even though most computers will throttle down the processor clocking and suspend a lot of other power using peripherals, you will still use less power having the unit off for the 30 mins or so.

However constantly turning the computer on and off, may cause a bit more wear and tear on the unit, causing a reduced lifespan.

answered Jan 23 '13 at 10:29

Garrett Fogerlie

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Reduced lifespan would mostly be rotating components: fans, hard drives. The electronics would not care too much. – John U Jan 23 '13 at 10:30
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@JohnU I would add that it may be a bit hard on the power supply and there may be some additional heat for the processor (I know my OC'd i7 jumps up in temp right as it is turning off.) – Garrett Fogerlie Jan 23 '13 at 10:35

Does shutting down and repowering CPU consume more energy?

1 Answers1