Does a hard drive's RPM affect battery life?

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andrw · #1 Post by **andrw** » Mon Jul 14, 2008 2:35 am

Will a 7200 RPM hard drive require more battery usage than a 5400 RPM one? I'm trying to configure a laptop that would use minimal energy. Thanks in advance for your help.

Wiz · #2 Post by **Wiz** » Mon Jul 14, 2008 5:20 am

Yes, if the battery life is most important to you then maybe the 5400 rpm is a better option since it use less power. I not sure how big the difference is and maybe it's minimal.
I just bought a T61p with a 250gb 5400rpm hdd and replaced with a 200gb 7200rpm. I didn't really compare how long the battery last, but regarding the performance the difference is nothing to worry about.

aaa · #3 Post by **aaa** » Mon Jul 14, 2008 6:59 am

The difference is minimal. Only thing I noticed about 7200rpm drives is that they are louder.

Wiz · #4 Post by **Wiz** » Mon Jul 14, 2008 10:46 am

aaa wrote:The difference is minimal. Only thing I noticed about 7200rpm drives is that they are louder.

That is also true. I always bought 7200rpm hdd's for my laptops because they are faster, but regarding the performance i find the difference to be minimal. I don't care that much what the benchmark says as long as i don't notice the difference under normal use. So if noise and battery life is important i think the 5400rpm HDDs is a better choice even if the battery life is only slightly enhanced.

kunfuchopsticks · #5 Post by **kunfuchopsticks** » Mon Jul 14, 2008 11:08 am

Easiest way would be to look at white papers or unit label for the current it draws; and compare that. I don't have either type drives handy.

#6 Post by **gator** » Mon Jul 14, 2008 11:10 am

The difference is minimal. I have checked this on multiple thinkpads ... however, 7200 rpm drives are noisier than the 5400 rpm ones (though this is getting better) and they also tend to heat up a bit faster.

makai · #7 Post by **makai** » Mon Jul 14, 2008 4:34 pm

Yup, 7200rpm definitely louder. More vibration too. I bought a 7200rpm 80 Hitachi a while back, and man was I disappointed. I could hear and feel the drive spinning all the time the laptop was on. It's now sitting in a USB enclosure!

I then went to a 120gb Seagate 5400rpm (oem), and sheesh... I can hear every click when it accesses. It's very annoying as intermittent HD access is not uncommon. Nothing is wrong with it data-wise, but still too noisy for me! It too is sitting in an enclosure!

My current drive is a 120gb WD 5400rpm (oem), and this one is a winner! So much so, I purchased 4 of them. The drive is extremely quite... and I do mean extrememly!!! There is also no vibration I can feel when it's spinning... which is most of the time.

Of course, ymmv for anything you end up purchasing. Good luck!

makai

#8 Post by **underclocker** » Mon Jul 14, 2008 9:16 pm

andrw wrote:Will a 7200 RPM hard drive require more battery usage than a 5400 RPM one? I'm trying to configure a laptop that would use minimal energy. Thanks in advance for your help.

Generally speaking, yes. Drives of similar vintage, will use more juice if they spin faster. However, some newer drives are more efficient than older drives, so it is best to know how efficient a particlular drive is before you buy it.

Below is a very comprehensive review of a dozen + drives, they include current drain for idle, transfer, write, read, seek, startup, and the label.

You'll get the picture --> http://www.digit-life.com/articles2/sto ... 7k100.html

Moderator note: Removed duplicate post from one minute back since this one has an additional sentence.

marvel · #9 Post by **marvel** » Sat Jul 19, 2008 4:16 pm

Toms hardware guide made a test of this a couple of years back (I´ll return with a link when I´ve found the page

). I remember someone mentioning the faster access times made the drive use shorter and thus reducing the power consumption.

Wiz · #10 Post by **Wiz** » Sat Jul 19, 2008 5:34 pm

marvel wrote:I remember someone mentioning the faster access times made the drive use shorter and thus reducing the power consumption.

The disk will not stop spinning even if you don't read or write anything and the 7200rpm drives spin faster. So i find it hard to believe in the theory that using a 7200 it's faster to read and write so the battery last longer. Of course using a very strict power setting you can tell the disk to stop spinning when idle after 1 minute, but that will be the same with 5400 and 7200rpm disks.
Some drives might have technology to reduce the power usage so it's not necessarily correct to say that all 7200rpm drives use more power then the 5400rpm either. Under normal use i believe the difference in speed and battery usage is minimal so i would worry more about the noise and heat. Also there are more then the RPM that decide how fast the disk is.

Maybe this is the page you where talking about:
http://www.tomshardware.com/charts/hard ... n,693.html

Troels · #11 Post by **Troels** » Sat Jul 19, 2008 7:00 pm

Well, looking from the step fesponse of a DC motor, it will spin up from 0 RPM to 7200 RPM at a given time (measured from 10% 90%). Making a similar step response, but showing the current draw as a function of time, the no-load motor draws a relatively high amount of current from the begging, but quickly goes to near zero mA. It will never reach zero, but it is very low.
By loading the motor, it will still draw the same amount of current at startup as the no-load drive, and still draw a considerable amount of mAs at steady state, while also spinning at a lower RPM.

In other words, the determination of if 5400 RPM or 7200 RPM draws more current, it is impossible to tell just from the RPM ratings.
Motors used for drives are typically chosen to meet a sweet spot of not loading the rotor fully so that full load equals the final drive RPM, i hope.

agarza · #12 Post by **agarza** » Sun Jul 20, 2008 7:56 pm

In my experience, some 7200rpm drives are noisier than others, or even comparing ones of the same model. I first bought one 60G E7K100 drive a while, after installing it on my T42p it vibrated a lot and very rapidly the palmrest got hot.
since the E7K100 is 'not meant' to be used as its brother the 7K100, I thought to buy a 100gig 7K100. No regrets here, I barely can hear the vibration and the noise emitted is no more audible than its brother.
Now the E7K100 sits on a USB2 enclosure.

AFAIK, battery consumption on 7200 is marginally higher than on slower drivers. however if you have 2 hdd running on battery you may see the difference, I have another 40GB 5400rpm sitting on the Ultrabay and now with a 2 year-old battery Im getting about 2 hours of battery life.

But for no reason in the world I would go back to a 5400rpm, the performance on a7200rpm is champ

Does a hard drive's RPM affect battery life?

Does a hard drive's RPM affect battery life?

Re: Does a hard drive's RPM affect battery life?

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