I'm planning to add a Samsung 830 (256GB) SSD to a MacBook Pro 13" (Mid-2012 model). It'll be installed into the default HDD area and the existing HDD will be moved into the optical drive bay.

Obviously Apple only enable TRIM on SSDs installed by themselves. Is there an official way to enable TRIM on an SSD the 'Apple way', or will TRIM Enabler be required? Can anyone offer some reassurance on using this software? I'm very wary of using it given that it's essentially a kernel hack.

  • No official way. Don't use Trim enabler, patch the kext yourself. – mspasov Nov 18 '12 at 19:03
  • No reason not to use Trim Enabler. Patching on your own has a way better chance to destroy your SATA driver than the automated way does. – bot47 Nov 18 '12 at 19:36
  • Do you have experience with this @MaxRied? I may just leave TRIM off altogether, given the input from Bill below. What would the performance degradation be like? Will it eliminate all 'risk' by not enabling TRIM? – Federer Nov 18 '12 at 19:48
  • I never had a problem with or without trim enabled. – bot47 Nov 19 '12 at 6:48
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    More on settings in OSX when using SSDs here: apple.stackexchange.com/questions/75921/… – greenforest Jan 3 '13 at 13:18

There is no official way to enable TRIM on non-Apple drives. In all likelihood, idle time garbage collection on a Samsung 830 will be sufficient to maintain performance so you might want to ignore TRIM unless you see a problem.

I've been using that drive in a late-2007 MacBook for months even when the drive is full and have not seen any issues without TRIM. Not an exact comparison as the lower speed interface on mine might mask any problems but still a positive sign.

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    Very positive indeed. I may just give TRIM a pass then. I'd rather eliminate all risk by not enabling TRIM and just buy another SSD when the performance runs down. But then again, if it'll last 1-2 years without that, I'll consider the money well spent. – Federer Nov 18 '12 at 19:53

The biggest argument I have against enabling TRIM is that TRIM is a SATA-only command.

What if the SSD is connected via PCIe, USB 3.0, FireWire, or Thunderbolt the Mac won't even recognize the drive as an SSD. Enabling TRIM would be USELESS for SSDs connected these other ways.

SSDs (such as OWC Mercury SSDs with SandForce controllers) have evolved to the point they don't need TRIM - particularly when the SSDs are not attached via SATA? They do their own garbage-collection and optimization. OWC - in particular - advises against enabling TRIM since this increases wear and tear on their SSDs. TRIM adds extra unnecessary writes when the SSD already did this on its own.

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