# SSD decreases battery life on MacBook Pro?



## Fox (Oct 4, 2002)

I recently purchased a Corsair Force 240gb SSD and installed it on my 13" MBP (2.24ghz, mid-2009, running latest version of Lion). I picked out this SSD specifically because it is better than most in power consumption (at least according to tests), but it seems to be actually decreasing my battery life, by 30-60 minutes, relative to the Seagate momentus 7200.4 320gb drive that I replaced it with. I installed and activated Trim Enabler, but other than that, the software is the same as that previously used on the Seagate drive. I examined running programs with Activity Monitor, and saw no unusual activity that would obviously drive up energy consumption. With the Corsair SSD, I not only notice the faster access times, but also that the MBP runs cooler and quieter, with the fan rarely going on. That should indicate reduced energy use, but that doesn't seem to be the case. I'm wondering whether the increased energy use is the cost of putting a non-Apple SSD into a MBP, or whether there are some settings I can tinker with that would reduce energy use by the SSD. Can anyone out there with an SSD in their Mac portable share their experience, or suggest a solution. If there isn't one, I'm inclined to put back the Seagate and put the SSD in my Mac mini.


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## Andrew Pratt (Feb 16, 2007)

The differences shouldn't be that much between the SSD and a regular drive according to reviews I've seen previously...and certainly not a hour difference to the worse. How did you clone the drives? I'm wondering if it was rebuilding indexes or something that caused the power increase as the SSD should be better if only a little.


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## Fox (Oct 4, 2002)

I initially put the SSD in a FW enclosure, and did a clean install of 10.7.0. I then used Migration Assistant to copy my home and other files to the SSD, followed by applying the combo-updater to bring the OS up to 10.7.4. I then replaced the mechanical HD with the SSD. Next I let the SSD build the Spotlight file. After that, I installed a bunch of updates on VirtualBox and VMware Fusion, followed by some updates on the VM's I have installed. (By the way, VM's restore much faster on the SSD.) I don't remember when I started running the MBP on battery power, but my sense of battery time was based on what I did after these steps; mostly browsing and email, with some testing startup speed of apps and a few VM's. I watched the changes in battery time remaining, and I checked wattage use a few times with Coconut Battery Monitor. I keep the backlight at half-power or less, bluetooth is turned off and had nothing plugged into ports except the little usb dongle that powers a wireless mouse. (Eventually I removed the dongle as well.) Based on reports of time remaining vs % charged, I am guessing that I now get 4.5 - 5 hours battery time with low level use (intermittent wireless browsing, email and reading documents). With the HD, I would have said I get 5 - 6 hours battery time doing same. The battery itself is the original, and it still has 90% capacity.


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## broad (Jun 2, 2009)

Fist thing I would do would be nuke and pave, but using a newly downloaded lion installer. If you re-download it you'll get 10.7.4 on the installer, not 10.7 and then update etc.

Edit: if the problem persists nuke and pave again using same new lion installer BUT run it as a fresh install for a bit and see if the trouble you perceive persists


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## Fox (Oct 4, 2002)

Just curious, broad, why do you think that the battery problem might be related to the version of the installer that I used?


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## pm-r (May 17, 2009)

Ouch!! I spent some time googling on 'SSD AND battery life' and was amazed to discover at those sites that did some actual testing (MacBook models and Windows laptops included) rather then those sites just repeating the misconception that an SSD uses less power because of the lack of moving parts.

NOT the case apparently, especially for any intensive apps other than light web browsing and email, and some suffered a drastic reduction in battery life.

The basic reasons provided it was due to the fact that:
- SSDs only have an On or Off state and currently no energy saving built in as nearly all HHDs have
and
- because the SSD can read/write so fast, it puts MUCH more stress on the CPU that ends up using way more power than any drive, SSD or HDD would ever consume.

It sure changed my misconception thinking about SSDs and battery life.


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## csonni (Feb 8, 2001)

I had the misunderstanding as well that installing SSD's in my MBP would increase the battery life due to no moving parts. Not that I use my battery a lot, but this is a disappointment.


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## pm-r (May 17, 2009)

Now if someone would like to send me 480GB SSD free and to keep, I'm sure I could do some additional testing. 

Oh yes, please also include a new replacement battery so that I have a good base to start from for my 15" 2.2GHz MBPro Mid/Late 2007 model.


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## PosterBoy (Jan 22, 2002)

On the flip side, even if there is a reduction in battery life (which I am sure there are some tricks to minimize) the machine should feel quite a bit faster now, yes? SSDs feed info to the rest of the machine so much more efficiently that I'd be surprised if things didn't feel downright zippy! How's the boot up / shutdown time, for example?? Put a MacBook Air next a Pro and you have have the air powered all the way up and back down again in the time it takes the Pro just to boot up.


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## krs (Mar 18, 2005)

PosterBoy said:


> How's the boot up / shutdown time, for example?? Put a MacBook Air next a Pro and you have have the air powered all the way up and back down again in the time it takes the Pro just to boot up.


I just did that a few days ago because I got a small MB Air which comes with a solid state drive.
The Air does boot up and shut down much faster which is obviously expected, but how often do people actually boot up and shut down?
I just let the Mac go to sleep to boot times are not really an issue.
Reduced battery life on a portable is.


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## PosterBoy (Jan 22, 2002)

krs said:


> I just did that a few days ago because I got a small MB Air which comes with a solid state drive.
> The Air does boot up and shut down much faster which is obviously expected, but how often do people actually boot up and shut down?
> I just let the Mac go to sleep to boot times are not really an issue.
> Reduced battery life on a portable is.


I actually pretty much never turn my iMac off. Or even let it go to sleep. But boot up and shut down times are a fairly good real world indicator of disk access speeds ;-)


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## krs (Mar 18, 2005)

PosterBoy said:


> But boot up and shut down times are a fairly good real world indicator of disk access speeds ;-)


True enough, but if you have sufficient RAM does a faster drive really speed things up in day to day use?
Probably depends what one uses the Mac for - in practice a 7200 rpm drive keeps up with what I need to do on the Mac.


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## PosterBoy (Jan 22, 2002)

krs said:


> True enough, but if you have sufficient RAM does a faster drive really speed things up in day to day use?
> Probably depends what one uses the Mac for - in practice a 7200 rpm drive keeps up with what I need to do on the Mac.


Depends on how much work you do that accesses the disk! Any app that stores a database of items (HELLO APERTURE) would load faster and major edits would save faster.

You're not wrong, it's not a boon to everyone, but to the fine folks who frequent a fiesta like this? Probably it will be!

Ha ha ha! Alliteration.


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## Fox (Oct 4, 2002)

There's no question that my MBP feels much snappier with the Corsair SSD in it than with the Seagate mechanical drive. But the performance with the Seagate was more than acceptable for what I use it for - word processing, email, browsing, spreadsheets, statistical analysis and some PowerPoint. The issue of battery life is much more important to me with a laptop, as I don't use my MBP very much unless I'm travelling. I am changing some settings that are supposed to help somewhat, and I'll reset the battery and test again, noting actual runtime. If I get less than 5 hours using the MBP for the things I usually use it for, the SSD will be removed and I'll use it in a 2011 Mac mini.

Edit: apparently you don't recondition the non-removable batteries like mine. I just need to test it some more.


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## broad (Jun 2, 2009)

Fox said:


> Just curious, broad, why do you think that the battery problem might be related to the version of the installer that I used?


i dont necessarily think that, but it would be good to rule it out. the more crap you can eliminate from an equation (older, potentially buggier installer, updates run which can possibly be wonky/corrupt) the easier it is to figure out where the problem stems from


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## Fox (Oct 4, 2002)

I found out about an inexpensive app called Battery Logger that apparently will keep track of battery runtime, as well as downtime from putting it to sleep. This will make it a lot easier to test actual battery time, rather than guessing from the constant changes in remaining battery time estimates.


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## voyager99 (Aug 29, 2005)

Doesn't make sense, this should *increase* battery life!


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## krs (Mar 18, 2005)

voyager99 said:


> Doesn't make sense, this should *increase* battery life!


What doesn't make any sense?

That an SDD takes more power than a regular hard drive?

There are lots of reasons why it could.
Just because something is solid state doesn't make it necessarily more energy efficient that other technology.


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## pm-r (May 17, 2009)

voyager99 said:


> Doesn't make sense, this should *increase* battery life!


That's what I originally thought and misunderstood until I did some actual checking as per my #6 post which you could also do or even have done some other checking before you posted your inaccurate and unfounded opinion remark.

And a bit strange, especially for a "Computer Science instructor"!!


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## dona83 (Jun 26, 2005)

Some SSDs are battery hogs. OCZ Vertex and Corsair GTs using Sandforce are some of the worst ones. I heard though that resetting the PRAM might allow the SSD to go into power saving standby mode a bit more.

I'd personally go with the OWC Electras for best battery life. The raw performance is not as good but it's still instant fast.


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## SINC (Feb 16, 2001)

My OWC Electra 480 GB gives me five full hours of battery life, more than enough for me on my 2.2 Ghz i7 MBP matte screen.


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## Fox (Oct 4, 2002)

To better quantify the difference in battery time between my new Corsair SSD and the Seagate 7200.4 mechanical drive, I ran four tests using Battery Logger to record battery time; two tests with each drive. The results seem to confirm my suspicion of longer battery time with the mechanical drive, though the difference was less than I suspected. Run times with the Seagate approached 5 hours; those with the Corsair approached 4 1/2, a 10% difference. However, the difference could have been less, as I did not standardize the tests with exactly the same activities. The activities I used in each case were a mix of word processing, calculations, email and internet, and there was sleep activity during each. Regarding the sleep activity, going by the change in % charge remaining, it seemed that a higher percentage of battery time was lost with the SSD during sleep than with the mechanical drive. However, I wonder if this wasn't because I followed the advice of an "energy saving" post, to uncheck allowing the HD to spin down during sleep for the SSD. 

Bottom line is that this particular SSD is fast, quiet and runs cool, but it is definitely not an energy saver in a MBP of my vintage (C2D), and the loss of battery time vs a mechanical drive is as much as 10%. I don't know if this would also be true had it been used in a Sandy Bridge MBP, but if battery run time is very important to you, I wouldn't recommend this model of SSD. In my case, battery run time is much more important than speed in a laptop, so the mechanical drive will stay and the SSD will be moved to my 2011 Mac mini. I hope this information helps others considering the use of an SSD in their laptops. It would be nice for others with SSD's to contribute their experience on runtime effects in their portable Macs.


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## i-rui (Sep 13, 2006)

new HDDs are indexed by spotlight by default (so they can be searched). perhaps a better way to test out the difference between your seagate and SSD would be to turn on privacy on both drives (through the spotlight preference pane) so they're not being indexed while running your battery test.


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## Fox (Oct 4, 2002)

I didn't run my tests until indexing for the new drive was completed. Presumably, battery life on both drives would be improved by turning off indexing. It would probably be improved even more if I turned off the wireless when I wasn't using it, which I didn't do. What I did do for both was to turn off bluetooth, turn off the backlit keys, and keeping the monitor backlighting to 50% or less.


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## dona83 (Jun 26, 2005)

In comparison, a WD Scorpio Blue uses 0.6-0.65W idle. A WD Scorpio Black uses 0.8W idle.


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