Does Disk Utility do TRIM for a 3rd party SSD?

I've been looking to upgrade the HDD in my 2012 MBP 15" now that SSD's are more affordable and given the Black Friday sale here in the US. I've done a lot of research on TRIM support for Macs prior to Yosemite but decided to wait, given the workaround one must employ, to see what Yosemite brought to the table. Here's what I've found regarding your questions:

1. TRIM support isn't a requirement for the 840 EVO series. Samsung implemented a controller, MEX, which allows the drive to manage garbage collection. This is similar to the Sandforce controller used on other drives (if you've heard of that) in that the SSD handles these tasks during system idle time. So without TRIM enabled you'll definitely want to leave your computer idle for periods of time here and there. However, TRIM allows the SSD to work with the OS in order to handle garbage collection more efficiently. This could mean better longevity with TRIM enabled. Regardless, with this specific drive, Samsung has released a firmware update that you should install (link at bottom of post). Note that some Mac users are finding the installation process difficult, resulting in using a Windows machine to reformat to NTFS to update, then back to OS X Extended (Journaled). The blog post linked below might have the workaround, though this is anecdotal and unverified by me.
2. I've read about the Disk Utility reports and I haven't been able to confirm whether it is reporting the TRIM command in use or simply another process by a similar name. However, I would not consider running Disk Utility periodically as a suitable workaround since the point of TRIM is for it to be in use on a continuous basis.

http://www.samsung.com/global/business/semiconductor/minisite/SSD/global/html/su pport/downloads.html

http://blog.conradchavez.com/2014/10/30/running-the-samsung-840-evo-ssd-performa nce-restoration-tool-on-a-mac/

I'm disappointed that Apple continues not to support third party SSD's. This is quite obviously, as others have pointed out, to Apple's monetary gain.

Edit: FWIW I'm upgrading to a Samsung 840 EVO and I'm going with the TRIM workaround for Yosemite that's been posted elsewhere. I don't see driver signage as a gaping security hole right now and, given the backlash from the professional community on this issue (which is depended on third party SSD support in Mac OS X), I suspect Apple will revise this policy at some point before the next OS release. Fingers crossed, and good luck.

TRIM is an SSD support function that's been causing a lot of confusion. This link in Wikipediagoes into considerable detail (nothing is ever simple) about what TRIM is, what its benefits are and why it's possible to get along without it. The take-away is that TRIM provides information to an SSD's internal Garbage Collection routines which can reduce wear and maintain speed over time. But since it's essentially reporting the freeing up of cells resulting from file deletion, it needs to be in operation full time. So if TRIM is not always active, the benefits of TRIM can't be realized.

If TRIM has been active on the drive in question, when you boot from another drive on which TRIM has also been activated and run Repair Disk in Disk Utility, at the end of the detailed list of what's being done, you should see "Trimming unused blocks" which is a succinct description of what TRIM does. And you should see an immediate, if small, jump in available space when the process is done.

Network 23 wrote:

If I understand this right, there's not much point in running Disk Utility if a TRIM utility hasn't been running already.

So to summarize what I learned from the two answers so far: For Yosemite the best thing to do is buy an SSD that is known to not need TRIM in the first place, and the 840 EVO is thought to be into that category. If you aren't forcing a TRIM utility to work in Yosemite, repairing the disk in Disk Utility is not going to be an effective workaround. If you must have TRIM you must turn off kernel signing but be prepared in case the Mac won't boot.

Because the operating system can write to an SSD's pages but must erase groups of pages (a block) at a time, and that can include pages which are still valid and which must be preserved by being copied and moved, using TRIM to identify the pages which can be ignored and just erased reduces the amount of data being rewritten, but if TRIM isn't active at the time a deletion occurs, the SSD treats the deleted file's page as still good, so it's unnecessarily written along with the good stuff. At the same time, I doubt any current SSD needs TRIM in order to function; it just doesn't function as well over the long term.

As far as the 840 EVO goes, this review addresses TRIM functioning with a surprise, which may be fixed with the firmware update garrettra recommends. And this review, for a different Samsung 840, seems to show that TRIM does, indeed, make a positive difference in Samsung SSD performance.

Another point as that while you can force "Trimming" using Disk Utility, it isn't necessary because the Garbage Collection routines can make use of the TRIM info (if it was generated in the first place) in their normal background process. Moreover, you can take other steps, beyond TRIM, to give the SSD a helping hand. One reflects the fact that SSD's silently do "wear-leveling" and make use of whatever "over-provisioning" space is built into most SSD's. You can add to that space by partitioning your SSD to leave some of its available space as free space (i.e., your partition is smaller than the maximum size you can make it) because it's accessible to the SSD controller even though it isn't to you.

While the driver signing in Yosemite is another effort by Apple to improve security, we've gotten by without out it since the beginning of OS X. My own solution has been to stay with an earlier OS for the time being. YMMV.😉

Network 23 wrote:

Yup, that's what I'm doing for now. Keeping my SSD-upgraded MacBook Pro on Mavericks.

Double Yup😉; TRIM is one reason I'm staying with Mountain Lion...

Okay, Yosemite supports TRIM for third-party drives -- sort of.

Some background -- a year ago I installed a 480GB Crucial M500 SSD into my mid-2010 MacBook Pro running Mavericks. I enabled TRIM and everything was wonderful.

Fast forward to a couple of months ago. I installed Yosemite and discovered, as everyone else has, that enabling TRIM doesn't work unless kext security is disabled. For me, that's too steep a price to pay for enabling TRIM, so I decided to live with Crucial's built-in garbage collection. Performance has been fine so far.

Today, my MacBook Pro's screen froze (I think the discrete video is going bad) so I rebooted into single user mode and ran 'fsck -fy' to make sure everything was good. Lo and behold, 'Trimming unused blocks' appeared on screen as the process wrapped up.

I must emphasize that TRIM is not enabled in my Yosemite install.

At this point, I booted from an external drive where I keep a SuperDuper! clone that is backed up every night. I mounted the SSD in Disk Utility and ran Repair Disk. Once again, 'Trimming unused blocks' appeared near the end of the process.

So the point here is that you do not need to use any TRIM enablers at all -- your Mac will TRIM the drive by running 'fsck -fy' in single user mode.

RicD wrote:

...So the point here is that you do not need to use any TRIM enablers at all -- your Mac will TRIM the drive by running 'fsck -fy' in single user mode.

Well, sort of...

As a test, I just turned off TRIM on my Crucial M500 running Mountain Lion and rebooted. In System Information, TRIM was no longer enabled for the SSD. I rebooted into Single User Mode and ran the fsck command. No Trimming of unused blocks appeared or occurred. I turned TRIM back on using TRIM Enabler, rebooted, checked TRIM status in System Info again and it was active. Rebooted yet again into Single User Mode, ran fsck and trimming unused block appeared as expected.

I tried something similar but this time booting from another internal OWC SSD, turning TRIM on and off and using Disk Utility on the M500 (since fsck only works on the boot drive). I got the same results.

Why we're getting different results is beyond me. But there's the additional complication that TRIM is a method of informing the SSD controller of blocks put in an unused status by file deletion on an ongoing basis, and is also the term used by the OS for the process of Trimming (as in haircuts) any blocks so identified. If blocks made unused by file deletion are not designated as such during the period when TRIM isn't active, they may be skipped over but the Trimming process would still take place when invoked.

Why it does that for you when TRIM is off but not for me is a conundrum. But if you check the TRIM support status using System Information>SATA/SATAExpress on your system, what does it say?

Like I said, TRIM is not enabled....

garrettra wrote:

I'm disappointed that Apple continues not to support third party SSD's. This is quite obviously, as others have pointed out, to Apple's monetary gain.

Apple does not manufacture SSD'd, whatever is fitted is 3rd party, even if Apple fitted it.

Third party is a misnomer, that's true, but they're being branded as such. At any rate this thread is referring to the lack of TRIM support for user-supplied and installed SSD's, e.g., not purchased/installed with a new Mac.

So while Apple may not make their own drives, they often fit drives that are not exactly like the ones you could get from the same manufacturer.

And that equates to a monetary gain how exactly?