# HDD power consumption question.



## Polarman (Jul 17, 2009)

I recently changed my 3 hard drives combo to just one. Purchased a WD Black 640GB as replacement.

I went on two power calculting website to figure out how much power i would save in getting rid of 2 hard drives. Both sites gave me a result of 50 watts in savings.

I don't really know if this is true or not. 25 watts per drive seems pretty darn high.

Anyway, i'm pretty sure that i'll comsume less energy with only one hard drive.


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## largon (Jul 18, 2009)

50W? 
BS.

Just look up the sticker on your HDD; there will be absolute maximum amperage ratings for 12V and 5V that the drive feeds on. For example my Samsung F1 640GB is rated 0.7A @ 12V and 0.5A @ 5V. That's maximum power draw of 13.8W. In reality the drive gets anywhere near that figure only during spin-up. Idle consumption should be ~5W or so, load read/write would be 1-2W more.


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## angelkiller (Jul 18, 2009)

Check here for some power measurements of some fairly common drives. On average a 7200rpm drive uses about 7-8W idle and 9-12W when seeking heavily.

The hdd label is a good source of info on its power consumption. However, I don't that that's the absolute maximum. I think the power supply calulator is correct. It its taking into consideration the startup current. When a hdd starts up, it draws a considerable amount of power (~20+W). But it's only for a fraction of a second. So if you were measuring power consumption, you wouldn't see a 50W drop, more than likely only around 15-18W on idle.


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