Side-by-side specifications of the Synology FS3400 and FS3420, from official datasheets. Differences are highlighted.
| FS3400 | FS3420 | |
| CPU | Intel Xeon D-1541 | Intel Xeon D-1739 |
| Cores / threads | 8-core | 8/16 |
| RAM (base) | 16 GB | 32 GB |
| RAM (max) | 128 GB | 192 GB |
| Drive bays | 24 | 24 |
| Expandable to | 72 | — |
| M.2 slots | null | — |
| Network | 2x 10GbE RJ-45, 4x GbE RJ-45 | 2x 10GbE RJ-45 |
| 10GbE | yes | yes |
| Max raw capacity | 1 PB | 1 PB |
| Hot-swap | yes | yes |
| Form factor | 2U rackmount | 2U rackmount |
| Released | 2022 | 2026 |