M.2 SSD cache performance for shared documents

TS-H1277AXU-RP is the NAS model.
Actually, read performance improvement will be sufficient.
I also want to learn that whether file caching relies on the file name or not.
Case 1 : user accessed a file, changed it and saved it .
Case 2 : user accessed a file, changed it and saved it under a new name.
Will that file be stored in the cache ,and can we benefit from read cache mechanism on the 2nd access at both of these cases too,
thanks