Side-by-side specifications of the Synology FS3017 and FS3400, from official datasheets. Differences are highlighted.
| FS3017 | FS3400 | |
| CPU | 2 x Intel Xeon E5-2620 | Intel Xeon D-1541 2.1 GHz |
| Cores / threads | 12 cores / 24 threads | 8 cores / 16 threads |
| RAM (base) | 64GB DDR4 ECC RDIMM | 16 GB DDR4 ECC RDIMM |
| RAM (max) | 512GB | 128 GB |
| Drive bays | 24 | 24 |
| Expandable to | 48 | 72 |
| M.2 slots | 0 | 0 |
| Network | 2 x 10GBase-T RJ-45 | 4 x 1GbE RJ-45, 2 x 10GbE RJ-45 |
| 10GbE | yes | yes |
| Max raw capacity | 72 drives | 184.32 TB |
| Hot-swap | yes | yes |
| Form factor | 2U rackmount | 2U rackmount |
| Released | 2017 | 2022 |
| Power consumption | — | 313.84 W / 125.77 W |
| DSM at launch | 6.1 | — |
Choose the FS3400 if you want the newer, more practical box: it uses a faster Intel Atom C3538-class CPU, supports much more RAM, and includes built-in 10GbE plus M.2 NVMe slots. The FS3017 is the older, bigger-chassis option with more raw front bays/expansion, but it lacks the FS3400’s stronger CPU/RAM ceiling and onboard 10GbE/M.2 convenience.