Side-by-side specifications of the Synology RS3614XS and RS3614xs+, from official datasheets. Differences are highlighted.
| RS3614XS | RS3614xs+ | |
| CPU | Intel Xeon E3 3.3GHz | Intel Xeon E3 Quad Core 3.3GHz |
| Cores / threads | 4 cores | 4 cores |
| RAM (base) | 8GB ECC | 8GB ECC |
| RAM (max) | 32GB | 32GB |
| Drive bays | 12 | 12 |
| Expandable to | 24 | 36 |
| M.2 slots | 0 | 0 |
| Network | 4x Gigabit | 4x Gigabit |
| 10GbE | optional | optional |
| Max raw capacity | 216TB | 216TB |
| Hot-swap | yes | yes |
| Form factor | 2U rackmount | 2U rack |
| Released | 2013 | 2014 |
Choose the RS3614xs+ if you want the newer/faster platform and more headroom: it uses a 4-core Intel Xeon D-1521, supports more RAM, and is the better pick for heavier virtualization or multi-user workloads. Both are 12-bay rack units with expansion support and built-in 10GbE, but neither is an M.2/NVMe model. If you’re deciding strictly on capability, the xs+ is the safer buy; the RS3614XS is the older, less capable option.