According to a source in OWC they do not recommend enabling TRIM on Mercury Extreme SSD as TRIM is only supported by Apple on Apple installed SSDs.

They suggest that I am better off using the build in data management in the SSD.

Is this scientifically founded in any way ?

Have any of you had success, failures or some knowledge with this ?

6 Answers 6


I now know a bit more.

I see three options after reading a lot of forums, AnandTech and Wikipedia:

  1. If I buy a Mac with a pre-installed SSD I'll get the power of TRIM for "free". The Apple supplied SSD are not the fastest on earth but they sure is way faster than your normal hard disk. Also, Apple uses well known more or less OEM.

  2. Buy an aftermarket SSD, clone, install and go. You will loose the power of TRIM but the SSD is still way way faster that your hard disk.

  3. Buy an aftermarket SSD, hack you kernel, run some kind of Trim Enabler for non Apple approved devices or what ever it takes, then clone, install and hopefully go.

If my mom, dad or average Joe were to buy a new Mac I would absolutely recommend #1. I'd personally go with #1 or #3 if I were going to buy one for my self.

If my mom, dad or average Joe were to upgrade an existing Mac I would have to go with #2 as Apple currently doesn't sell any SSD online (not as far as I can see anyway) and I would not recommend #3 in any form or factor. If I were to upgrade my own Mac I would start with #3 and revert to #2 in case of any problems.

I hope this didn't end up as a buyers guide as prohibited in the FAQ as I have not recommended any specific model or brand. My intentions is only to share some personal thoughts.

All in all, I will try TRIM for myself on my own SSD but I would not recommend anyone that doesn't understand the risk or are unable to fix any problems by them self.

Any thoughts ? Am I way off scale here ?

  • I NEVER buy an upgraded hard drive from apple. The HDD's they provide are slow (5400 rpm) and both the HDD and SSD options are substantially overpriced. If you're afraid of installing a drive yourself (warranty and such) you can bring it in to apple and as a 'Level 1' repair it should only cost you 20$.
    – Roy
    Commented Jul 18, 2012 at 21:56
  • Roy: Apple does not offer the installation of third-party components as a service. Contacting an AASP (Apple Authorized Service Provider) is a better option. Commented Jan 16, 2013 at 2:15

It depends on which SSD you have. Anand of Anandtech (one of the most comprehensive and knowledgeable sites on SSDs) has confirmed (and others have reported) issues using the TRIM enabler on the latest generation of Sandforce-based SSDs (the SF-2281 controller), which includes newer OWC drives, and many others (including OCZ Vertex and Agility 3, some Corsair Force drives). I have an OCZ Vertex 2 (older generation Sandforce) and haven't tried the TRIM enabler.

I'd recommend caution - unless you're finding noticeable performance degradation, probably best to stay away. SSD controllers are still somewhat unpredictable, and it's unlikely Apple has done testing of its TRIM implementation with drives other than the Toshiba and Samsung ones it uses.

  • I'd like to add that TRIM enabler should not be used with ANY SandForce controller. It has issues and is not required. SF garbage collection does a better job than TRIM.
    – user10355
    Commented Jan 24, 2012 at 16:25

This may not answer your question but it should reassure you.

I put an OWC SSD in my last MacBook Pro, pre-lion and used it for a year. No trim and it was controlled by an early SandForce disk controller.

I had absolutely no problems with this SSD, none. It was so fast it blew my mind and gave me another year of use on an older machine. Since then OWC/SandForce has come out with a firmware update to that original SSD although I sold the machine before that happened and now use a machine with an Apple-supplied SSD running with Lion and no doubt trim enabled.

Truth be told, the Apple supplied SSD isn't quite as fast as the OWC although both are so much faster than a hard disk the difference doesn't bother me.

I would not worry about the trim issue but I would back up your SSD daily as anyone with any kind of storage (HD, SSD or flash memory) should do.


I have a hard time believing TRIM actually causes a problem with any particular SSD. If the SSD manufacturer thinks that the TRIM command causes a problem, they can choose to not execute the command in their firmware. I guess it is possible that OS X's TRIM command is somehow non-standard, maybe it violates some part of the ATA spec for TRIM, but I also find that pretty hard to believe.

I've been using a Intel X-25M (gen 2) for a couple of years now, and I used the TRIM Enabler many months ago. I got better performance after enabling it and doing some quick maintenance and I haven't had a single problem. I haven't run the enabler for Lion yet as the utility doesn't yet support it.


The problem I've found with my 2007 Macbook/Lion and an OWC SSD (Mercury) is frequent 30 second freezes. They were so frequent with FileVault2 that I had to stop using it and they are much more frequent when OS X starts swapping pages (so I have to restart applications as soon as memory used gets over 3.95GB. It's not so bad that I've gone back to a hard disk but it is annoying. I've got 35GB free on the drive and leave it idle for long periods but there's clearly some kind of low-level issue between the controller and OS X.

There were similar reports with lots of beach balls when people tried enabling TRIM on non-Apple SSD's under Snow Leopard.

OWC Tech support says that they have not had any similar reports but I'd guess that few people are running their SSD's on systems as old a mine.

This is a long-winded way of saying I think it depends on both the SSD and the Mac model so unless you find someone with the exact same configuration, you won't know the answer until you try it.

  • It seems to me that there is no right or wrong answer. So a guide with models of the ssd and mac and os version would ve cool. But looking in the faq it seems to be to close to a buyers guide.
    – Benjamin
    Commented Nov 11, 2011 at 19:38
  • I upgraded the firmware yesterday and the problem seems to be gone. Upgrading was not that easy as the OS X upgrade only works on selected models and using the Boot Camp/Windows upgrade didn't work either. It finally worked when I did it using my Windows system. Commented Nov 12, 2011 at 20:30

I've had very strange behavior and failure of an Intel 510 in a 2011 Mac mini; with no TRIM support. I've just enabled TRIM for that drive and that seems to have solved it. Check out my post: SSD behaves strangely, then suddenly fails, but checks show no problems

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