Side-by-side specifications of the Synology DS408 and DS409, from official datasheets. Differences are highlighted.
| DS408 | DS409 | |
| CPU | — | 1.2GHz |
| Cores / threads | — | — |
| RAM (base) | 1 GB | 256MB |
| RAM (max) | — | — |
| Drive bays | 4 | 4 |
| Expandable to | — | — |
| M.2 slots | 0 | 0 |
| Network | 1 GbE | 1x Gigabit |
| 10GbE | no | no |
| Max raw capacity | 4 TB | 4TB |
| Hot-swap | yes | yes |
| Form factor | desktop | desktop |
| Released | 2008 | 2009 |
Choose the DS409 if you want the clearly stronger platform: it has a faster CPU, more RAM headroom, and more drive bays/expansion than the DS408. Neither model includes 10GbE or M.2. The DS408 is only the better pick if it is much cheaper and you only need the smaller, older unit.