Side-by-side specifications of the Synology RS1221+ and RS1221RP+, from official datasheets. Differences are highlighted.
| RS1221+ | RS1221RP+ | |
| CPU | AMD Ryzen V1500B | AMD Ryzen V1500B |
| Cores / threads | 4 cores / 8 threads | 4 cores / 8 threads |
| RAM (base) | 4 GB DDR4 ECC SODIMM | 4 GB DDR4 ECC SODIMM |
| RAM (max) | 32 GB | 32 GB |
| Drive bays | 8 | 8 |
| Expandable to | 12 total with RX418 | 12 with RX418 |
| M.2 slots | 0 built-in; optional adapter card | 0; optional adapter card |
| Network | 4 × 1GbE RJ-45 | 4× 1GbE RJ-45 |
| 10GbE | optional | optional |
| Max raw capacity | 108 TB single volume | 108 TB single volume |
| Hot-swap | yes | yes |
| Form factor | 2U rackmount | 2U rackmount |
| Released | 2021 | 2020 |
| Power consumption | 49.89 W / 22.64 W | 61.94 W / 29.98 W |
| DSM at launch | — | — |
They’re the same 8-bay platform with 2x eSATA expansion support and no built-in M.2 slots; for storage/expansion, there’s no real difference. The decisive gap is the RP model’s redundant power supplies, while both use the same CPU class and have the same RAM ceiling and 10GbE via add-in card. Choose the RS1221RP+ if uptime matters; otherwise the RS1221+ is the cheaper, simpler pick.