Side-by-side specifications of the Synology RS3621xs+ and SA3600, from official datasheets. Differences are highlighted.
| RS3621xs+ | SA3600 | |
| CPU | Intel Xeon D-1541 | Intel Xeon D-1567 |
| Cores / threads | 8 cores / 16 threads | 12 cores / 24 threads |
| RAM (base) | 8 GB DDR4 ECC UDIMM | 16 GB DDR4 ECC RDIMM |
| RAM (max) | 64 GB | 128 GB |
| Drive bays | 12 | 12 |
| Expandable to | 36 | Up to 168 additional bays |
| M.2 slots | 0 (via PCIe adapter cards) | 0 |
| Network | 4×1GbE RJ-45, 2×10GbE RJ-45 | 4 x 1GbE RJ-45, 2 x 10GbE RJ-45 |
| 10GbE | yes | yes |
| Max raw capacity | 1 PB single volume | 192 TB internal; 1536 TB with expansion |
| Hot-swap | yes | yes |
| Form factor | 2U rackmount | 2U rackmount |
| Released | 2021 | 2019 |
| Power consumption | — | 500 W / unknown |
| DSM at launch | — | 6.2 |