Side-by-side specifications of the Synology DS215j and DS215+, from official datasheets. Differences are highlighted.
| DS215j | DS215+ | |
| CPU | Marvell Armada 375 | dual-core 1.4GHz |
| Cores / threads | 2 | 2 |
| RAM (base) | 512MB DDR3 | 1GB |
| RAM (max) | 512MB | 1GB |
| Drive bays | 2 | 2 |
| Expandable to | 0 | 0 |
| M.2 slots | 0 | 0 |
| Network | 1x Gigabit | 2x 1GbE RJ-45 |
| 10GbE | no | no |
| Max raw capacity | 12TB | 16TB |
| Hot-swap | yes | yes |
| Form factor | desktop | desktop |
| Released | 2015 | 2015 |
Pick the DS215+ if you want the faster x86 CPU, more RAM headroom, and better headroom for heavier DSM apps or multitasking; the DS215j is the cheaper ARM-based option with less memory and lower performance. Neither model has 10GbE, M.2, more than 2 bays, or expansion support, so the real deciding factors are CPU and RAM ceiling.