You can however turn on TRIM support through a series of Terminal commands and script execution or by using a free utility called Trim Enabler. You restart your Mac every couple of weeks, holding down the Option key during the reboot, then let it sit at the boot menu for 24 hours as the firmware cleans the SSD.

Crucial told me I had two options: occasionally 'clean' the SSD or enable the operating system to send TRIM commands to the drive. I contacted Crucial technical support to ask if the Crucial 512GB M4 SSD I purchased supported TRIM. This is something you’ll want to address. The bottom line is that without TRIM enabled the performance of an SSD will suffer over time. There is some great information on it on Wikipedia’s TRIM entry. TRIM is effectively a garbage collection model for SSDs. Derek brought up the issue in the comments and I spent some time investigating it. After adding a 3rd party SSD to your Mac, you need to investigate TRIM support.Hat tip to Eytan for pointing this out to me. At 820MB/s it is over 5 times faster than the SSD I just installed. Though quite a bit more expensive than a standard SSD, if you want the absolute best performance for a Mac Pro you may want to consider it. An SSD is a good performance upgrade but the OWC Mercury Accelsior_E2 provides incredible performance.There were two important things I found out after I started reading the comments from that entry: We’ve enabled it on a pair of older Macs in the Orbiting HQ with aftermarket SSDs in them, and so far we’ve had no issues-giant scary warning notwithstanding.As I wrote last week, the SSD upgrade for my Mac Pro went very smoothly. Called trimforce, the utility can be executed from the OS X terminal, and it requires a reboot to start working. With today’s OS X 10.10.4 update, however, Apple has added a command line utility that can be used to enable TRIM on third-party SSDs without having to download and install anything. If you took a Mac that originally came with a spinning disk and installed an aftermarket SSD in it yourself, the operating system wouldn’t use TRIM on the disk-at least, not unless you resorted to third-party tools. The lone exception to that list has been Apple’s OS X, which-at least until today-only supported TRIM on its OEM SSDs. Pretty much every operating system in use these days supports TRIM-a special ATA command that the OS sends along to an SSD when deleting files on that SSD. Further Reading Ask Ars: “My SSD does garbage collection, so I don’t need TRIM… right?”

Force enable trim mac os