Open up Windows Explorer, <right-click> on your SSD Volume/Properties/Tools TAB/Optimize There you can manually OPTIMIZE (Trim) your volumes or Check/Schedule your optimization on all drives.
You should see the currently scheduled frequency on the "Optimize" tab that Froggy mentioned. It's scheduled to run weekly by default, but that can be changed with the "Change Settings" button on that same tab.
OPTIMIZE as an option only exists in Win8.x and 10, especially as far as scheduling is concerned. There is a small FREE app called SSDtool that runs just fine on Win7 and will allow you to MANUALLY Trim your SSDs... this is what I use periodically. Windows 7 itself will TRIM as necessary when files are deleted (just as Win8.x and 10 do) but it has no TRIM manual or scheduling function, just a defrag, which you do not want to do to an SSD.
therollbackfrog: thanks for the tool i have not come across it before. Looks like i can take my xp ssd out of the laptop and force trim on it periodically.
Sure, but you need to be sure that the OS you're mounting it in knows that it is an SSD or TRIM won't be available on that drive. You can always try it and if you have a disk activity light on your System, you'll know it's TRIMming 'cause that light will light up like a Christmas Tree when TRIM is being perfomed.
Also, if that SSD is fairly new, its Garbage Collection processing will take care of that SSD pretty well on its own... those processes have gotten very intelligent over the years.
Its an old 30gig SSD so is fairly old. Checking the activity light though is a good idea. Would using a task manager like processs hacker works as well? (the tower is under the desk and so is not too easy to see) Maybe a certain process comes up with disk activity? (mb/s)
The process will not generate but a tiny bit of mB/s due to the size of the disk transaction being performed (it's very small), what it will do is saturate the disk queue (100%) until the TRIM is complete. Under W7 you can see this by firing up the RESOURCE MONITOR, selecting the Disk TAB, expand the STORAGE element and sort its display by Logical disk (so you can see your SSD's volume). When you run the TRIM operation, as soon as the OS feels this type of operation can be tolerated (TRIM is a non-Queued operation... can't be stacked very well and will slow down the disk queue if it wants to be busy) you'll see its "Active Time" column jump to 100% (probably in spurts) and you should be able to see it. The Volume rarely ever gets that busy unless you're running some large disk intensive operation in the background.