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HDD power consumption question.


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Jun 24, 2008
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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.
May 6, 2005
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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.
May 16, 2008
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North Carolina
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.