Side-by-side specifications of the Synology DS120j and DS124, from official datasheets. Differences are highlighted.
| DS120j | DS124 | |
| CPU | Marvell Armada 3700 88F3720 | Realtek RTD1619B 1.7 GHz |
| Cores / threads | 2 cores / 2 threads | 4 cores / 4 threads |
| RAM (base) | 512 MB DDR3L | 1 GB DDR4 non-ECC |
| RAM (max) | 512 MB | — |
| Drive bays | 1 | 1 |
| Expandable to | 0 | 0 |
| M.2 slots | 0 | 0 |
| Network | 1 x 1GbE RJ-45 | 1× 1GbE |
| 10GbE | no | no |
| Max raw capacity | 16 TB | 108 TB |
| Hot-swap | no | no |
| Form factor | Desktop | Desktop |
| Released | 2020 | 2025 |
| Power consumption | — | — |
| DSM at launch | — | — |
Choose the DS124 unless you only need the cheapest possible single-bay NAS: it has a much faster Realtek RTD1619B CPU and 1 GB of RAM versus the DS120j’s weaker Marvell Armada 3700 and 512 MB. Both are 1-bay units with no expansion, and neither has 10GbE or M.2 slots, so the DS124 is the better home/SMB pick for general use and light multitasking.