Side-by-side specifications of the Synology DS218j and DS218PLAY, from official datasheets. Differences are highlighted.
| DS218j | DS218PLAY | |
| CPU | Marvell Armada 385 88F6820 | Realtek RTD1296 |
| Cores / threads | 2-core | 4-core / 4-thread |
| RAM (base) | 512 MB | 1 GB DDR4 |
| RAM (max) | 512 MB | 1 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 | no |
| Form factor | desktop | 2-bay tower |
| Released | 2018 | 2018 |
Choose the DS218PLAY if you want the better CPU and more headroom: it has a Realtek RTD1296 quad-core 1.4 GHz processor and 2 GB RAM max, versus the DS218j’s Marvell Armada 385 dual-core 1.3 GHz and 512 MB RAM max. Both are 2-bay units with no expansion, no 10GbE, and no M.2 slots, so the real deciding factor is CPU/RAM; for light file sharing the 218j is fine, but the 218PLAY is the safer pick for media and multitasking.