How to restore your SSD to peak performance

“Back in the days when mechanical hard drives with spinning platters were the norm, you could simply hand your old hard drive to a deserving relative or friend as an upgrade, get a thank you, and call it a day,” Jon L. Jacobi reports for PCWorld. “It’s not so simple with today’s solid-state drives.”

“In many cases, used SSDs simply aren’t as fast as newer ones. The biggest issue in retasking, reselling, or even maintaining an SSD for a prolonged period stems from an inconvenient characteristic of NAND flash memory: Previously written cells must be erased before they can be rewritten with new data,” Jacobi reports. “If the SSD is forced to reuse cells rather than use new ones while storing data, performance will plummet.”

“Simply deleting files and repartitioning and formatting your drive won’t do the trick, however, as those operations take place at levels above where true garbage collection occurs,” Jacobi reports. “In fact, due to the total absence of utilities that force complete garbage collection, there’s only one way to return an SSD to pristine, like-new condition — the ATA secure-erase command.”

Much more in the full article here.


  1. I have a third party SSD in my 2008 MBP. OSX doesn’t support those natively, but TRIM Enabler sorts that out. Install and turn on, restart into Single-user mode for an fsck -y, and then boot back into full OSX. Apart from confirming it’s still enabled after doing an OSX update you’re done from that point on.

  2. There are faster, longer life SSDs at reasonable prices on the horizon. I’d also expect Apple is investigating how to keep SSDs at peak efficiency, similar to their successful work keeping hard drives running well via background defragmentation of files.

    There have been reports that Gibson Research Corporation’s SpinRite is successful at restoring SSD’s efficiency. Except Steve Gibson, bless him, is off on another research project (SQRL) and has yet to finish a Mac compatible version of his software.

  3. How SSDs work lends itself to how I’ve been using Macs for years, even before SSDs. Have a fast relatively small-capacity internal drive with your OS and app files, and put your user data on a large external drive, where speed is not as critical (for most people).

    This practice reduces data fragmentation (and wear-and-tear) on the internal hard drive and maintains performance levels close what you get after a “clean install,” for a much longer time (without any maintenance procedures). Most of the performance-degrading “data churn” happens when constantly writing and erasing user data on the hard drive. If you are mostly writing OS and app files to the key “startup disk,” such files do not change as often, so ongoing fragmentation is greatly reduced. The system still writes temp files (such as for caches and virtual memory) while operating, but as long as plenty of free space is maintained, performance does not degrade noticeably over time.

    The added benefit of this approach is the ease of “data migration” to a new Mac. Since most of your user data is on the external drive, just connect it to your new Mac. SSDs are still quite expensive, so you can get one that is smaller; it only needs to be large enough to comfortably hold your OS and app files.

      1. No, I think Fusion Drive will actually accelerate the problem described in this article by constantly and automatically moving data to and off the SSD portion of the combined SSD/HD logical disk. You have the advantage of needing a smaller SSD to have greatly improved performance, but if close to 100% of the SSD portion is always occupied with data, then the performance hit from having to “reuse” (erase before writing new data) exists, which is the problem described in this article.

        Still, Fusion Drive is much better than a hard drive by itself. And it is simpler than keeping your user data on a separate drive. But it is not better in terms of long-term performance (for the problem described in this article) without the need for periodic maintenance steps, compared to keep a separate “startup disk” with your OS and app files.

        1. “if close to 100% of the SSD portion is always occupied with data, then the performance hit from having to “reuse” (erase before writing new data) exists”

          While 4GB of the SSD will get re-used. Even at it’s slowest performance ever in it’s lifetime, it’s still going to be exponentially faster than reading/writing to/from a mechanical drive.

          If 128GB isn’t large enough for your applications on the SSD portion you could always “roll your own”.

          Sure you could also have another SSD as your data drive, but with PCIe flash storage etc. you’re still going to be much faster by letting the fusion drive do it’s thing even if the data drive is mechanical.

          The only time I’d stay away from fusion is if you have over 124GB of applications and you are working with individual files above 4GB in size.

  4. I’ve yet to hear anyone comment that their SSD is now running slow after prolonged usage. Has anyone on this site experienced this first hand. Or… Do we simply get SSD theoretical slow down articles with no real issues coming from the end user.

  5. This article should be retitled to “What people running Windows pre-Win7 should do if they have an SSD (besides killing themselves)”.

    Seriously, don’t attempt do what this article suggests on a Mac.

    1) It’s a waste of time.
    2) If you don’t know what you’re doing, you’re potentially putting your data at risk.
    3) You’re putting unnecessary wear on your SSD.

    If you have a Mac with an Apple installed SSD, TRIM is already enabled in OS X, and is doing its job.

    If you have a Mac with a 3rd party SSD, get a 3rd party TRIM enabler and let it do its job.

    While I’m at it, if you have any SSD on a Mac, don’t ever defrag. However, if you have a hard drive on a Mac, you’re most likely never going to need to defrag on OS X. There are rare exceptions where you’d see a benefit for defragging a hard drive, such as routinely filling up a hard drive, even then the benefit may not be worth it.

    1. —–“This article should be retitled to “What people running Windows pre-Win7 should do if they have an SSD (besides killing themselves)”

      Thanks for the laugh!

    2. you are just the average user, so don’t talk – there are thing about computers that you clearly don’t understand! – reading mac-something or windows-something is nothing. go underground,deep, if you want to learn. your sad, any sad WILL degrade over time, trim is just for the average joe that is reading emails,presentation,office ,maybe a little movie making and photoshop….

      1. Judging by your comment, English doesn’t appear to be your primary language, which is fine, but I don’t think you fully understood the article or my comment.

        The article has been updated since my comment back in January. See the bottom of the page:
        “The original version of the article implied that performing the secure erase function regularly could increase the performance of modern SSDs. The article has been updated to clarify the specific situations in which performing the secure erase function is beneficial.

        As my comment mentioned, this article simply doesn’t apply to Mac users or users of Windows 7 or later.

        Secure Erase as maintenance won’t speed up SSDs where TRIM is enabled, and in fact, is just a waste of time and puts unnecessary use-cycles on the SSD. TRIM is enabled on Windows 7 and greater as well as on OS X where there are Apple installed SSD or via 3rd party software for 3rd party SSDs.

        It does matter how you are using an SSD whether it’s for email, porn, video production or in a server, TRIM is what you want to use and it makes Secure Erase as maintenance unnecessary.

        LIkewise, it’s foolish to defrag an SSD.

        As for me, no, I’m not an average user. I ran one of the largest Apple Authorized Service Centers for a few years, have produced tech articles and shows for print, online, radio and TV. I currently co-own a company that consults with one of the largest SSD manufacturers in the world.

  6. I am having a slowdown problem with my late 2012 Mac Mini with a fusion drive. The computer is heavily used for about 8 hours a day and has about 600 gb towards the 1 TB capacity.

    The computer is intermittently slow: I mean almost hanging occasionally for 3 or 4 seconds while some program boots up. There is no pattern to the behaviour, but it started when the drive reached 50% capacity. I’ve used permissions repair and checked everything as best as I can with disk tools, but the problem persists.

    Meanwhile I can hear the disk chugging away during breaks, obviously seriously rearranging things.

    That’s all I know to this point.

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