Side-by-side specifications of the Synology FS3420 and FS6400, from official datasheets. Differences are highlighted.
| FS3420 | FS6400 | |
| CPU | Intel Xeon D-1739 | 2x Intel Xeon Silver 4110 |
| Cores / threads | 8/16 | 16c/32t |
| RAM (base) | 32 GB | 32 GB |
| RAM (max) | 192 GB | 512 GB |
| Drive bays | 24 | 24 |
| Expandable to | — | 72 |
| M.2 slots | — | 0 |
| Network | 2x 10GbE RJ-45 | 2x 1GbE + 2x 10GbE RJ-45 |
| 10GbE | yes | yes |
| Max raw capacity | 1 PB | 184.32 TB |
| Hot-swap | yes | yes |
| Form factor | 2U rackmount | rackmount |
| Released | 2026 | 2025 |