Side-by-side specifications of the Synology RS3626xs and RS4017xs+, from official datasheets. Differences are highlighted.
| RS3626xs | RS4017xs+ | |
| CPU | Intel Xeon D-1726 | Intel Xeon D-1541 2.1 GHz, burst up to 2.7 GHz |
| Cores / threads | 6 cores / 12 threads | 8 cores / 8 threads |
| RAM (base) | 8 GB DDR4 ECC UDIMM | 8 GB DDR4 ECC UDIMM |
| RAM (max) | 48 GB | 64 GB |
| Drive bays | 12 | 16 |
| Expandable to | 36 | 24 (2 × RX1217/RX1217RP2) |
| M.2 slots | 0 built-in; optional via adapter card | 0 |
| Network | 2× 10GbE RJ-45, 1× out-of-band management LAN | 2 × 10GbE RJ-45; 4 × 1GbE RJ-45 |
| 10GbE | yes | optional |
| Max raw capacity | 36 drives | 400 TB |
| Hot-swap | yes | yes |
| Form factor | 2U rackmount | 3U rackmount |
| Released | 2026 | 2017 |
| Power consumption | 147.79 W / 75.73 W | — |
| DSM at launch | — | — |
Choose the RS4017xs+ if you need more headroom: it has a newer/faster CPU, much higher RAM ceiling, and more bays plus better expansion potential than the RS3626XS. The RS4017xs+ also typically gives you built-in 10GbE, while the RS3626XS is the older, more limited platform; neither is a strong M.2-first choice. For a home/SMB buyer, the RS4017xs+ is the safer long-term pick unless price is the only priority.