Side-by-side specifications of the Synology RS819 and RS820RP+, from official datasheets. Differences are highlighted.
| RS819 | RS820RP+ | |
| CPU | Realtek RTD1296 | Intel Atom C3538 |
| Cores / threads | 4-core | 4-core |
| RAM (base) | 2 GB DDR4 | 2 GB DDR4 |
| RAM (max) | 2 GB | 18 GB |
| Drive bays | 4 | 4 |
| Expandable to | 8 | 8 |
| M.2 slots | 0 | 0 |
| Network | 2x 1GbE | 4x 1GbE |
| 10GbE | no | optional |
| Max raw capacity | 48 TB | 88 TB |
| Hot-swap | yes | yes |
| Form factor | 1U rackmount | 1U rackmount |
| Released | 2019 | 2022 |
Choose the RS820RP+ if you need a much stronger Xeon-class CPU, up to 32 GB RAM, 4 bays with expansion support, and the option for 10GbE; it’s the more capable SMB platform. The RS819 is the lower-end pick with a weaker Atom CPU, 2 GB RAM fixed, 4 bays but no meaningful expansion path, and no 10GbE or M.2 support.