Replicate TRIM with a Mac SSD
If you have an SSD on your Mac, listen up. You can replicate TRIM SSD functionality in Mac OS X by using this great tip from one of our readers, here’s Curt explaining: “I just got a MacBook Air and like many others I was surprised to learn Mac OS X doesn’t support TRIM. I found a workaround, here it is:”
Update 2: You can use a third party TRIM enabler tool for Mac OS X 10.6.7 or later, that actually enables TRIM rather than trying to replicate it.
Update / Warning: There have been reports that using this method slows down the SSD’s speed. Excessive writes to an SSD can also limit its lifespan. Until Mac OS X natively supports TRIM, your best bet may be to backup your files, reformat the drive, and then copy the files back to the drive (frustrating, I know). You may wish to read the comments below before trying this out on your own SSD drive. Proceed at your own risk and always have a complete file system backup handy!
- Launch Disk Utility, located in /Applications/Utilities/
- Select your SSD from the left side drive list
- Click on the “Erase” tab (don’t worry it won’t start formatting things)
- Look for and click on the “Erase Free Space” button near the bottom as seen in the screenshot
- Let the “Erase Free Space” function run
- Close Disk Utility when it’s finished
Curt describes how this work as follows: “What this does is write 0’s over previously deleted files, which makes it easier to later write to that block again, this is similar to the TRIM function. Here’s a simplification of how TRIM works for comparison; it clears deleted blocks on the SSD so that they are understood as empty when it’s time to write back to that block. I would recommend using this tip about once a month as a regular system maintenance plan, or after deleting a large amount of files from your SSD.”
We edited the instructions and provided a screenshot for clarity, but thanks for sending this great tip in Curt!
It’s a little strange to me that Mac OS X does not currently have TRIM support built in, despite Apple selling the MacBook Air with SSD and offering the SSD upgrade on most other Macs for sale. I don’t have an SSD to test this out but the theory behind it makes some sense.