Side-by-side specifications of the Synology DS115j and DS120j, from official datasheets. Differences are highlighted.
| DS115j | DS120j | |
| CPU | Marvell Armada 370 800 MHz | Marvell Armada 3700 88F3720 |
| Cores / threads | 1 core / 1 thread | 2 cores / 2 threads |
| RAM (base) | 256 MB DDR3 | 512 MB DDR3L |
| RAM (max) | 256 MB | 512 MB |
| Drive bays | 1 | 1 |
| Expandable to | 0 | 0 |
| M.2 slots | 0 | 0 |
| Network | 1 x Gigabit Ethernet | 1 x 1GbE RJ-45 |
| 10GbE | no | no |
| Max raw capacity | 5 TB | 16 TB |
| Hot-swap | no | no |
| Form factor | Desktop | Desktop |
| Released | 2015 | 2020 |
| Power consumption | 14.5 W / 3.85 W | — |
| DSM at launch | — | — |