Side-by-side specifications of the Synology FS3017 and FS3400, from official datasheets. Differences are highlighted.
| FS3017 | FS3400 | |
| CPU | 2x Intel Xeon 6-core | Intel Xeon D-1541 |
| Cores / threads | 12 cores/24 threads | 8-core |
| RAM (base) | 64 GB | 16 GB |
| RAM (max) | 512 GB | 128 GB |
| Drive bays | 24 | 24 |
| Expandable to | 72 | 72 |
| M.2 slots | null | null |
| Network | 2x 10GbE RJ45 | 2x 10GbE RJ-45, 4x GbE RJ-45 |
| 10GbE | yes | yes |
| Max raw capacity | 108 TB | 1 PB |
| Hot-swap | yes | yes |
| Form factor | Desktop | 2U rackmount |
| Released | 2017 | 2022 |
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.