Side-by-side specifications of the Synology DS211j and DS212, from official datasheets. Differences are highlighted.
| DS211j | DS212 | |
| CPU | Marvell 88F6281 | 1.6GHz |
| Cores / threads | 1/1 | — |
| RAM (base) | 128 MB | 256MB |
| RAM (max) | 128 MB | — |
| Drive bays | 2 | 2 |
| Expandable to | 0 | 0 |
| M.2 slots | 0 | 0 |
| Network | 1x Gigabit Ethernet | 1x Gigabit |
| 10GbE | no | no |
| Max raw capacity | 6 TB | 6TB |
| Hot-swap | no | yes |
| Form factor | Desktop | Desktop |
| Released | 2010 | 2011 |
| Power consumption | 28.2 W / 9.5 W | 18.2 W / 6.8 W |
| DSM at launch | — | — |
Choose the DS212 if you want the clearly better box: it has a faster CPU and a higher RAM ceiling than the DS211J, which makes it the more capable home/SMB NAS. Both are 2-bay units with no expansion path, and neither has 10GbE or M.2.