Side-by-side specifications of the Synology RS3614xs+ and RS3621XS+, from official datasheets. Differences are highlighted.
| RS3614xs+ | RS3621XS+ | |
| CPU | Intel Xeon E3 Quad Core 3.3GHz | Intel Xeon D-1541 |
| Cores / threads | 4 cores | 8/16 |
| RAM (base) | 8GB ECC | 8 GB |
| RAM (max) | 32GB | 64 GB |
| Drive bays | 12 | 12 |
| Expandable to | 36 | 36 |
| M.2 slots | 0 | 2 |
| Network | 4x Gigabit | 4x 1GbE/10GbE RJ-45 |
| 10GbE | optional | yes |
| Max raw capacity | 216TB | 1 PB |
| Hot-swap | yes | yes |
| Form factor | 2U rack | 2U |
| Released | 2014 | 2025 |