I’ve found that Roon running on a Mac Mini (8Gb RAM) as Core is very stable. I use Raspberry Pi / HiFiBerry and Bluesound endpoints.
Biggest difference to performance was an inexpensive upgrade - bought an external USB3 200Gb SSD (£90) and use this as boot drive / where Roon database is stored. Library (about 6,500 CDs) sits on a 3Tb USB3 (not SSD) external drive. Running OS and Roon database on SSD made a big improvement to the speed of operation e.g. how quickly search results are returned - it’s now almost instantaneous.