I managed to play roon without any problems by using an old qnap server as roon core server, with 3 GB of ram. CPU load was always low, but ram usage was close to 99% all the time.
Library was 4-5 TB, literally huge, flacs from cd's.
I had some delay with tidal though, i think because of poor internet speed.
Now i am using a new qnap server with 8GB of ram, TS 673. It is working without any problems.