Side-by-side specifications of the Synology RS409RP+ and RS411, from official datasheets. Differences are highlighted.
| RS409RP+ | RS411 | |
| CPU | unknown | 1.6 GHz |
| Cores / threads | unknown | 1/1 |
| RAM (base) | unknown | 512 MB |
| RAM (max) | unknown | 512 MB |
| Drive bays | 4 | 4 |
| Expandable to | 4 (via RX4) | 0 |
| M.2 slots | 0 | 0 |
| Network | 2 x Gigabit | 2 x Gigabit Ethernet |
| 10GbE | no | no |
| Max raw capacity | 8 drives | 16 TB |
| Hot-swap | yes | yes |
| Form factor | 1U rackmount | 1U rackmount |
| Released | 2009 | 2010 |
| Power consumption | 61 W / 29 W | 53 W / unknown |
| DSM at launch | 2.1 | 3.0 |
Choose the RS411: it has a faster 1.6 GHz Marvell CPU versus the RS409RP+’s 1.2 GHz PowerPC, and supports up to 1 GB RAM versus 512 MB. Both have four bays with no expansion, and neither supports 10GbE or M.2, so the RS409RP+ only makes sense if redundant power supplies are essential.