Apple security measures penalise OS X Yosemite users with third-party SSDs

“Apple users are being warned that security measures introduced in OS X Yosemite can adversely affect performance if they are have a third-party solid state drive (SSD) fitted in their Mac,” Daniel Robinson reports for V3.

“The issue, which has come to light since Yosemite was released, concerns the Kernel Extension (Kext) signing capability that Apple has introduced in OS X Yosemite,” Robinson reports. “This is intended to ensure that low level system drivers are approved and unaltered by malware, by blocking drivers without a valid signature.”

Robinson reports, “However, a knock-on effect of this feature is that it can stop the Trim driver for third-party SSDs from running.”

Read more in the full article here.


        1. No, that’s not possible. TRIM commands are sent by the operating system to the SSD based on its knowledge of the file systems and the blocks they use or don’t use. The SSD can do garbage collection and use some other methods to lessen the need for TRIM, but it’s not the same as TRIM.

          OWC says this themselves here:

          “Through the DuraWrite technology, over-provisioning, and the garbage collection in the SandForce processer of our OWC Mercury SSDs, the need for TRIM is negated.”

        2. Umm, so basically what I said is correct. It’s immune unless you enabled TRIM via the command line. While TRIM is not technically on the SSD chipset, Durawrite is which pretty much does the same thing. Got it.

    1. I just installed OWC’s Data Doubler into my Mac mini using the existing 750GB HDD and OWC’s 480GB SSD to create a custom Fusion Drive. I started out using an OS X 10.8.x installer disk I created on a thumb drive. I than installed 10.8.x, ran all the updates, then installed all my applications with a Tech Admin account. Only after all that did I upgrade to Mavericks’ and then ran Migration Assistant from a Time Machine backup. By going this route, I had no problems with the complete system rebuild.

      I guess on new machines that only run the latest version of OS X, you don’t have that option. Haven’t tried it yet, but eventually, one of my clients are going to want me to upgrade one of their systems to Fusion Drive. I’ll have to see how that goes.

  1. Trim on SSD is a very complicated subject. You would need a much more informative article to get anything useful out of it. I’m not an expert, but I know enough that say Trim is often not required for SSDs and only improves performance of SSD’s in certain situations.

  2. First you post an article about this non-issue on November 13, and then again on November 17. Stop perpetuating this silly nonsense, MDN.

    TRIM is not nearly as crucial as the folks who are writing these articles suggest. SSDs are constantly evolving, and manufacturers are including built-in garbage collection functionality in their drives that supersedes TRIM. Some SSD manufacturers don’t even recommend enabling TRIM support (OWC, for instance). And even Crucial, a well-respected manufacturer, says the difference for most use cases is negligible and may not be noticeable by end users:

    I’ve had multiple SSDs in Macs for years without TRIM enabled and haven’t seen any performance degradation at all. This “issue” is effectively much ado about nothing.

        1. So some Samsung SSD models have noticeable performance degradation without TRIM enabled, while models from Crucial, OWC, and others do not. Needless to say I’ll be avoiding Samsung SSDs based on this information.

          I’m still curious whether Howie’s Toshiba performance suffers without TRIM enabled.

        2. This is beside the point. Apple should not restrain trim use to only the SSD it sell, this is bad selling practices. All SSD supporting trim should be recognized by OS X.

  3. I’ve been using software called Trim Enabler for quite some time. It keeps TRIM running on my Mac mini, which has a third party SSD installed. I have had no performance hits at all. The only annoyance is that every time there is an update to OS X, I have to re-enable TRIM, and then reboot again. No big deal really.

    1. You’ve missed the point of the article. In Yosemite, a new security feature was added, required all Kext files to be signed. This is a good thing.

      The side effect, due to Apple’s refusal to support Trim on 3rd-party drives, is that users must now choose between using Trim (via Trim Enabler), or having better security. I have a Corsair SSD that I’ve been using for 1.5 years, and I had to disable the security feature (Trim Enabler will do it for you). See more information here:

    1. SSDs will outlive most consumer hard drives – with or without TRIM enabled:

      SSDs have no moving parts to fail. They consume way less power, run way cooler, and are therefore much more durable. Also, when write operations are finally exhausted on an SSD, you don’t suddenly lose access to your data as you do when hard drives die; instead you have read-only access to the data on the SSD.

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