A Trim command which allows an operating system to inform a solid-state drive (SSD) which blocks of data are no longer considered in use and can be wiped internally.
Trim was introduced soon after SSD’s started to become an affordable alternative to traditional hard disks. Because low-level operation of SSDs differs significantly from hard drives, the typical way in which operating systems handle operations like Erasing, Formatting resulted in unanticipated progressive performance degradation of write operations on SSDs
In other words, TRIM helps to maintain the performance of solid-state drives (SSDs) at an optimal level over the lifetime of the drive.
TRIM functions by actively deleting invalid data from the SSD’s memory cells to ensure that write operations perform at full speed.
Before EL Capitan Trim must be enabled by custom patches for Third-party SSDs
sudo trimforce enable
You might see the following warning
IMPORTANT NOTICE: This tool force-enables TRIM for all relevant attached devices, even though such devices may not have been validated for data integrity while using TRIM. Use of this tool to enable TRIM may result in unintended data loss or data corruption. It should not be used in a commercial operating environment or with important data. Before using this tool, you should back up all of your data and regularly back up data while TRIM is enabled. This tool is provided on an “as is” basis. APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, REGARDING THIS TOOL OR ITS USE ALONE OR IN COMBINATION WITH YOUR DEVICES, SYSTEMS, OR SERVICES. BY USING THIS TOOL TO ENABLE TRIM, YOU AGREE THAT, TO THE EXTENT PERMITTED BY APPLICABLE LAW, USE OF THE TOOL IS AT YOUR SOLE RISK AND THAT THE ENTIRE RISK AS TO SATISFACTORY QUALITY, PERFORMANCE, ACCURACY AND EFFORT IS WITH YOU. Are you sure you wish to proceed (y/N)?
then type ‘y’ press & Enter once again type ‘y’ press & Enter, after few minutes your System will reboot & your SSD will support Trim
Note: In some hard disk, enabling trim may cause unexpected data loss & file corruptions, which may even cause booting issue so safeguarding your personal data and files, personally, I do not recommend force turning on TRIM.