Side-by-side specifications of the Synology DS418j and DS418play, from official datasheets. Differences are highlighted.
| DS418j | DS418play | |
| CPU | Realtek RTD1293 | Intel Celeron J3355 |
| Cores / threads | 2-core | 2/2 |
| RAM (base) | 1 GB DDR4 | 2 GB |
| RAM (max) | 1 GB | 6 GB |
| Drive bays | 4 | 4 |
| Expandable to | 0 | 0 |
| M.2 slots | 0 | 0 |
| Network | 1x 1GbE RJ-45 | 2x 1GbE |
| 10GbE | no | no |
| Max raw capacity | 40 TB raw | 40 TB |
| Hot-swap | no | yes |
| Form factor | desktop | desktop |
| Released | 2018 | 2017 |
Choose the DS418play if you want the stronger CPU and more headroom: it’s the better pick for Plex/transcoding, and it supports 2 GB RAM max versus the DS418j’s lower, more basic memory ceiling. Both are 4-bay units with no expansion, and neither has 10GbE or M.2. If you only need simple file storage and backups, the DS418j is the cheaper, more basic choice.