The TRIM Command
The TRIM command helps the OS clean up data in storage blocks that are no longer needed. This optimizes the write performance of an SSD by keeping more blocks of data free to be written to. It also prevents the SSD from being so aggressive in cleaning up after itself that it causes wear on the memory chips. In this way, it prevents premature failure. TRIM is supported in OS X Lion (10.7) and later for all drives, but it’s enabled by default only on Apple-supplied SSDs. It’s not clear why Apple limited TRIM support this way, but the conventional wisdom is that TRIM implementation is up to the SSD manufacturer, and each one uses a different TRIM methodology. As such, Apple chose to use TRIM only on SSDs that it has certified. A few third-party utilities can enable TRIM for non-Apple-supplied SSDs, including TRIM Enabler. These utilities make use of Apple’s built-in TRIM support while removing the ability of the OS to check if the SSD is on Apple’s list of approved manufacturers.
Should You Use TRIM?
Some early-generation SSDs had unusual implementations of the TRIM function that could lead to data corruption. For the most part, these early SSD models are difficult to come across, unless you picked one up from a source that specializes in used products, such as flea markets, swap meets, and eBay.
Is Your Mac Running TRIM Already?
If your SSD came installed on your Mac, TRIM is on by default. However, if you added an SSD later, it might not be. Here’s how to check:
Enabling TRIM
To turn TRIM on: Press enter.
