That is peculiar, it suggests some kind of memory leak where the Roon processes grow and eventually start thrashing. My Roon Core runs perfectly on an i5 NUC with 8GB of main memory running Ubuntu Server 18.10, serving 1508 albums, 18960 tracks from a Synology NAS. There are 3 main Roon processes:
- RoonAppliance: 2.8GB virtual, 687MB resident.
- RAATserver: 905MB virtual, 29MB resident
- RoonServer: 549MB virtual, 37MB resident
All in all, much less than physical main memory. But nothing else much runs on this machine.