The TRIM command, available on most recent models of SSD (Intel controller: Indilix and SandForce mainly), allows some modern operating systems (Linux from Kernel 2.6.33 and Windows 7 all versions), to avoid a drop performance over time. It is used to erase the memory cells that directly related to the deletion of a file, in order to optimize subsequent entries.
To use the TRIM command, you need a compatible SSD, the drivers of the motherboard controller must be compatible and you must have Windows 7(XP and Vista does not support natively TRIM)
My SSD supports TRIM?
To find out, download the software CrystalDiskInfo: here
Once executed, verify that "TRIM" appears in bold in the "features" line. If TRIM is grayed out, your SSD does not support the command. But check the manufacturer's website, it is possible that the firmware supports is available.
In the screenshot below, it is a Corsair SandForce controller, it handles perfectly the TRIM command.
You will notice that this software provides a wealth of info on all your storage units.