Side-by-side specifications of the Synology DS1515 and DS1517+, from official datasheets. Differences are highlighted.
| DS1515 | DS1517+ | |
| CPU | quad-core CPU | Intel Atom C2538 |
| Cores / threads | 4 | 4c/4t |
| RAM (base) | 2GB | 2 GB |
| RAM (max) | 6GB | 16 GB |
| Drive bays | 5 | 5 |
| Expandable to | 15 | 10 |
| M.2 slots | 0 | 2 |
| Network | 4x 1GbE | 4x1GbE |
| 10GbE | no | optional |
| Max raw capacity | 40TB | 108 TB |
| Hot-swap | yes | yes |
| Form factor | desktop | desktop |
| Released | 2015 | 2017 |