Side-by-side specifications of the Synology RS3617xs and RS3617xs+, from official datasheets. Differences are highlighted.
| RS3617xs | RS3617xs+ | |
| CPU | Intel Xeon E3-1230v2 3.3GHz | Intel Xeon D-1531 2.2 GHz |
| Cores / threads | 4 cores / 8 threads | 6 cores / 12 threads |
| RAM (base) | 4GB DDR3-1600 ECC | 8 GB DDR4 ECC UDIMM |
| RAM (max) | 32GB | 64 GB |
| Drive bays | 12 | 12 |
| Expandable to | 24 | 24 (2× RX1217/RX1217RP) |
| M.2 slots | 0 | 0 |
| Network | 4x 1GbE RJ-45 | 4× 1GbE RJ-45; 2× 10GBase-T RJ-45 |
| 10GbE | optional | yes |
| Max raw capacity | 96TB internal; 288TB with 2 expansion units | 360 TB |
| Hot-swap | yes | yes |
| Form factor | 2U rackmount | 2U rackmount |
| Released | 2017 | 2017 |
| Power consumption | — | — |
| DSM at launch | — | — |
Choose the RS3617xs+ if you want the higher-end platform: it has a faster Intel Xeon D CPU, supports more memory, and is the better fit for heavier virtualization or multi-user workloads. Both are 12-bay 3U units with expansion support, 10GbE, and no built-in M.2 slots, but the + model is the safer long-term buy if the price gap is small.