Side-by-side specifications of the Synology DS423 and DS425+, from official datasheets. Differences are highlighted.
| DS423 | DS425+ | |
| CPU | Realtek RTD1619B | Intel Celeron J4125 |
| Cores / threads | 4/4 | 4/4 |
| RAM (base) | 2 GB DDR4 | 2 GB |
| RAM (max) | 2 GB | 6 GB |
| Drive bays | 4 | 4 |
| Expandable to | 0 | 0 |
| M.2 slots | 0 | 2 |
| Network | 2x 1GbE RJ-45 | 1x1GbE + 1x2.5GbE |
| 10GbE | no | no |
| Max raw capacity | 108 TB | 108 TB |
| Hot-swap | yes | yes |
| Form factor | Desktop | desktop |
| Released | 2026 | 2025 |
Choose the DS425+ if you want a faster Intel CPU, a higher RAM ceiling, and NVMe M.2 slots for cache or storage; it’s the better SMB pick for multitasking and heavier apps. The DS423 is the simpler, cheaper option, but it has a weaker CPU, lower RAM ceiling, and no M.2; neither model gives you built-in 10GbE, and both are 4-bay units with no expansion to 5+ bays.