Side-by-side specifications of the Synology RS818+ and RS819, from official datasheets. Differences are highlighted.
| RS818+ | RS819 | |
| CPU | Intel Atom C2538 | Realtek RTD1296 |
| Cores / threads | 4-core | 4-core |
| RAM (base) | 2 GB | 2 GB DDR4 |
| RAM (max) | 16 GB | 2 GB |
| Drive bays | 4 | 4 |
| Expandable to | 8 | 8 |
| M.2 slots | 0 | 0 |
| Network | 4 x 1GbE | 2x 1GbE |
| 10GbE | optional | no |
| Max raw capacity | 80 TB | 48 TB |
| Hot-swap | yes | yes |
| Form factor | 1U rackmount | 1U rackmount |
| Released | 2017 | 2019 |
Choose the RS818+ if you want the stronger platform: it has a Celeron J3455, supports more RAM, and is the one with expansion options and 10GbE support. The RS819 is the simpler unit: weaker CPU, lower RAM ceiling, no expansion, no 10GbE, and no M.2. For a home/SMB buyer, the RS818+ is the better pick unless you only need basic 4-bay storage.