Side-by-side specifications of the Synology RS818+ and RS819, from official datasheets. Differences are highlighted.
| RS818+ | RS819 | |
| CPU | Intel Atom C2538, 2.4 GHz | Realtek RTD1296, 1.4 GHz |
| Cores / threads | 4 cores / 4 threads | 4 cores / 4 threads |
| RAM (base) | 2 GB DDR3 non-ECC SODIMM | 2 GB DDR4 non-ECC |
| RAM (max) | 16 GB | 2 GB |
| Drive bays | 4 | 4 |
| Expandable to | 8 total with RX418 | 8 total with 1× RX418 |
| M.2 slots | 0 (optional M2D18 adapter) | 0 |
| Network | 4 x 1GbE RJ-45 | 2× 1GbE RJ-45 |
| 10GbE | optional | no |
| Max raw capacity | 80 TB raw with RX418 (4 x 10 TB internal plus expansion) | 48 TB internal; 96 TB with RX418 |
| Hot-swap | yes | yes |
| Form factor | 1U rackmount | 1U rackmount |
| Released | 2018 | 2018 |
| Power consumption | 45.28 W / 20.81 W | 28.31 W / 10.1 W |
| DSM at launch | — | — |
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.