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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20" iMac 2.66 ghz Core 2 duo, 2009 & 2012 mac minis and 2013 13" MacBook Air
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.
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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20" iMac 2.66 ghz Core 2 duo, 2009 & 2012 mac minis and 2013 13" MacBook Air