I upgraded my NAS at home from an old Synology DS212j to a DS716+ last year and it was a significant improvement. The DS212j was great for what it was intended to do: backups and storage but not much else. The DS212j just didn’t have enough power to run apps efficiently.
The DS716+ is shipped with 2GB installed. This allows it to run some applications without any issue. I do have some problems with Plex every once in a while so I looked into what I could do to speed it up. The memory on the unit is expandable to 8GB so that was an easy choice.
I checked out this post on the Synology forum. This upgrade took about 2 minutes. Just unscrew the front case and remove the drives. The memory slot is on the bottom of the case. I can see performance improvement in the NAS during multitasking.
The DS212j is still working well and is dedicated to backups.