The only idea I could think of is below, I'm curious if there is a more direct way to tell if TRIM is actually doing something rather than showing as "supported" only

I did the following scenario on my C300 (which supposedly have TRIM, as verified via CDI and fsutil reports TRIM is passed), on an eSATA port (should not matter, it's a pass-through, not RAID):
- copy a fairly large file to the SSD (~1GB)
- delete it
- use an unerase utility to recover the file to another drive
- compare original file with the recovered file

Turns out I got a complete match If TRIM is working, the file should not match at all (it should be either all zeroes or all ones depending on how the SSD interprets TRIMmed pages). I expected that at least a good deal of the file would not match as a second option, but I got a full recovery (one case where I don't want a full recovery of data)

One thing that comes to mind is that the SSD only marks the pages unused, but a GC actually erases the blocks some time later only and the SSD treats the pages as valid until that time - this should not be so, but that would not be the first time something isn't as it should be.
I also tried to recover a file that is quite older (a few days) - almost perfect recovery also So either TRIM does not work, or GC is ridicolously slow.

Ideas?