I know this is an old thread , but I’m posting here to confirm that DSM works just fine if these machines, even 6.2.2.
I have the TS5400D (4-bay, Atom D2550). It can be upgraded to 4GB RAM, but I’ve never seen it use even 1GB. I’m guessing if you try to run a bunch of dockers it will struggle but it’s just fine as a file server.
Install process is a little involved for 6.2+ but doable. I’ll try to post more details when I’m all dialed in.