Solid-State Drives (SSD) use a data writing mode that erases old data before writing the new data, unlike traditional disks that overwrite data directly. This feature causes SSDs to be more efficient but slower. To solve the problem, Microsoft built in a set of TRIM commands into the Windows 7 operating system exclusively for SSDs. When an SSD deletes files, it simply marks the location of a block as deleted. Then it waits until the system is idle to start completing the actual space-cleaning work to avoid reducing speed.
In addition, if your system disc is an SSD, TRIM commands can automatically disable features such as defragmentation, ReadyBoost, and so on. Although they were originally designed for traditional hard drives, unnecessary writing actions decrease the lifespan of SSDs. Moreover, to enable TRIM commands, both the operating system and SSD master chip must provide support simultaneously to ensure TRIM commands work properly; ADATA SSD products support TRIM commands.
Compared to Garbage Collection, which is operated by the SSD controller and firmware, TRIM commands are performed under OS command to mark out the files that are ready to be deleted. As a result, when the system is idle, the SSD will erase blocks that are marked for deletion. Because the block has been pre-cleaned and become blank, subsequent data can be written in directly; therefore an SSD’s optimal writing speed can still be maintained.