The Synology DS220+ makes do with 6 GB max — soldered base plus one slot

The DS220+ ships with 2 GB soldered and no easy upgrade path — you get one SO-DIMM slot for up to 4 GB more, topping out at 6 GB total. Synology officially says 6 GB max, so don’t expect to push past that. It’s a bit stingy for a modern NAS, but fine for basic file serving and Surveillance Station.