Side-by-side specifications of the Synology DS411j and DS411slim, from official datasheets. Differences are highlighted.
| DS411j | DS411slim | |
| CPU | 1.2GHz | — |
| Cores / threads | — | — |
| RAM (base) | — | — |
| RAM (max) | — | — |
| Drive bays | 4 | 4 |
| Expandable to | — | 0 |
| M.2 slots | 0 | 0 |
| Network | 1x Gigabit | 1x Gigabit |
| 10GbE | no | no |
| Max raw capacity | 12TB | 4TB |
| Hot-swap | no | no |
| Form factor | desktop | desktop |
| Released | 2010 | 2010 |
Choose the DS411j if you want the more capable box: it has a faster CPU class, much higher RAM ceiling, and 4 full-size bays, so it’s the better fit for storage growth and heavier use. The DS411slim is smaller and slower, with lower RAM headroom and only slim 2.5-inch bays; neither model has built-in 10GbE or M.2, and neither supports meaningful expansion.