On the iMac there is some thermal sensor that connects to the hard drive and makes this a bit tricky since non-Apple SSDs don't have that feature. Is this true for the 2011 MacBook Pros?

  • Until someone actually has one to check, it would be hard to say. However on the 2010 MacBook Pro there isn't one that I am aware of. I swapped the drives out in mine without any issues. Commented Feb 24, 2011 at 16:46
  • I also have the 2010 MacBook Pro and swapped out the HD with an SSD. No problems.
    – Kris
    Commented Feb 24, 2011 at 18:35
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    I have two followup questions: 1) Will TRIM work out-of-box or does this require a first-party drive? 2) Does the OS install any differently to an SSD or can I mirror my existing drive?
    – Justin
    Commented Mar 22, 2011 at 23:05

2 Answers 2


I replaced the stock 500GB 5400rpm hard drive in my Early 2011 Mac Book Pro (MacBook Pro 8,2) with a 120GB OWC Mercury Electra 6G SSD a few weeks ago. There was no thermal sensor attached to the stock drive. So far the replacement has worked fine, no issues at all.

Hardware Monitor application reports the temperature of the SSD, so the computer must be properly polling the internal temp sensor in the drive (over the SATA interface,) and/or there may be a permanent sensor attached near the drive on the inside of the MacBook Pro's case. (But not actually attached to the drive.)

Screen capture of output from Hardware Monitor: Screenshot of output from Hardware Monitor app

There was no difference in the software install process (vs. a regular hard drive.) In fact, I used 2 external cases (and a 3rd, separate, bootable drive) to do a block copy from the original 500GB to the new 120GB SSD. No issues.

About TRIM support: The drive itself is capable of it (See "TRIM Support" at the bottom of the specs page for this drive.), however, Mac OS X 10.8.2 does not support TRIM for this drive, at this time. The drive vendor OWC says you don't need TRIM anyway because SandForce's firmware makes it unnecessary or even counterproductive. I agree with their explanation.

Screen cap from my System Profiler:

enter image description here

As another data point on SSDs -- I had a 60GB OWC Mercury 3G SSD in a 2009 Mac Mini for about 3 years, never had any problems with it whatsoever.

2013-04-30 UPDATE -- I had some firmware problems with the new 120 GB OWC Mercury 6G drive. The drive would not be recognized at system startup time without doing multiple (10 or more) PRAM & SMC resets. Finally it would "catch on" & then start up and run fine for weeks. Eventually it stopped responding altogether. (OWC had suggested that I apply a firmware update, but I wasn't able to do this because I don't have a working DVD reader / writer.)

I am returning the drive to OWC for a warranty replacement. It always pays to BACK UP YOUR DATA every single day, or even several times a day.

  • A most excellent report. Having people share what works and how they know it makes this a great place for technical answers. Thanks!
    – bmike
    Commented Feb 20, 2013 at 17:59
  • FYI, Crucial and other SSD manufacturers have a component finder on their websites that help you get the correct RAM, SSD, etc. that work on your particular MBP. Commented Feb 20, 2013 at 18:40
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    Update as of 2013-03-19 -- continued reliable operation with the OWC SSD, no problems.
    – gosmond
    Commented Mar 20, 2013 at 2:43
  • Update 2013-04-30 -- firmware problems, returning the drive under warranty. ALWAYS back up your data, every day.
    – gosmond
    Commented Apr 30, 2013 at 17:39
  • Update 2013-10-10 -- drive replaced under warranty in mid-May 2013, and moved it into a new 2012 Mac Mini 2.6Ghz core i7. Running fine, no problems since the replacement.
    – gosmond
    Commented Oct 10, 2013 at 17:21

As long as you have the correct screwdriver(s) for internal access you can replace the HDD with an SSD.

I apologize for not catching the full question.

Folks at iFixit did a teardown of the 15" and there is no thermal sensor attached the HDD.

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    The question is does it have some thermal sensor that won't be connected so the fans will always be off or always on. Commented Feb 26, 2011 at 18:14
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    @BrianCarlton, the thermal-sensor issue is addressed in detail in my answer, above.
    – gosmond
    Commented Feb 21, 2013 at 9:33

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