Side-by-side specifications of the Synology DS218j and DS218+, from official datasheets. Differences are highlighted.
| DS218j | DS218+ | |
| CPU | Marvell Armada 385 88F6820 | Intel Celeron J3355 |
| Cores / threads | 2-core | 2C/2T |
| RAM (base) | 512 MB | 2 GB |
| RAM (max) | 512 MB | 6 GB |
| Drive bays | 2 | 2 |
| Expandable to | — | 0 |
| M.2 slots | 0 | 0 |
| Network | 1x 1GbE | 1x 1GbE RJ-45 |
| 10GbE | no | no |
| Max raw capacity | 20TB | 20 TB |
| Hot-swap | no | yes |
| Form factor | desktop | desktop |
| Released | 2018 | 2018 |
Choose the DS218+ if you want noticeably more headroom: it has a stronger Intel CPU and a much higher RAM ceiling than the DS218j, so it’s better for Plex, Docker-like packages, multiple users, and heavier file services. Both are 2-bay units with no expansion, and neither offers 10GbE or M.2. Pick the DS218j only for basic backup and simple file sharing on a tighter budget.