Physicist Considers Whether Turning Off Your PC Saves Power

The logical thing would be to think that if you turn off the computer, you will save more energy than if you leave it on to not be using it, right? And indeed, it is. If you turn off your computer while you are eating, you will save some energy, help the planet and not lose money. But these modest energy savings will have the disadvantage of shortening the life of your computer, with the advanced generation of waste that entails.

We have already said that you can save power turning your computer off, but since that also shortens the life of the computer, you have to really find out how much the savings will be. That way, we can assess whether it is worth it or not to take the trouble to turn it off.

To clarify how much energy a normal computer consumes during its different states and processes of use, we ask the Harvard University physicist, Wolfang Rueckner, to do some tests with his iMac G5 computer from 2005. It was quite surprising to discover that when turning it on or off, the machine consumed about 130 watts (a measure of the amount of energy used at each instant, the power). But it consumed 92 watts while it was on without doing anything and only an efficient 4 watts when hibernation mode was selected. And finally, off I used 2.8 watts because it remained plugged into electricity anyway, a very common practice that also happens in our homes with small appliances, a process in which it continues to consume even little. Something that generates a very low but very constant expense, by the way.

If we add to these accounts the consumption of the maximum peak that happens when we turn it off and on, in the end, it turns out that the electricity consumed by the computer if it is turned off for an hour is slightly less than if we leave it hibernating.

John Phillips

I am involved in Machine Learning and Artificial Intelligence technologies and am also a technical consultant. In my spare time I research where AI is headed and write for this website when I find an interesting story.

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John Phillips