Keep TRIM on.
This article explain why :
http://arstechnica.com/gadgets/2015...garbage-collection-so-i-dont-need-trim-right/
But to summarize it :
Garbage collection isn't another way to do the same thing that TRIM do on a SSD (even if peoples mistakenly talk about TRIM and GC as competing technologies), actually TRIM make Garbage Collection more efficient. Having TRIM on on a SSD is always a good thing.
Basically, TRIM tell the SSD (which do garbage collection) what files are actually deleted by the OS. Without TRIM, the SSD have no way to tell the difference between the big 4 GB movie you saved in your folder, and the 4 GB movie you deleted a while ago. Since the OS doesn't physically delete files, but simply keep note to "himself" that this space can be written on if need be, on the SSD level, those big chunk of date are like any other chunk, and the SSD cannot do proper garbage collection of this chunk of space to be efficient when this space will be needed for something else.
Also, TRIM doesn't give you a "performance boost", but simply help a lot to make sure that the performance you had at first will remain.