Side-by-side specifications of the Synology RS1219+ and RS1221RP+, from official datasheets. Differences are highlighted.
| RS1219+ | RS1221RP+ | |
| CPU | Intel Atom C2538, 2.4 GHz | AMD Ryzen V1500B |
| Cores / threads | 4 cores / 4 threads | 4 cores / 8 threads |
| RAM (base) | 2 GB DDR3L non-ECC SODIMM | 4 GB DDR4 ECC SODIMM |
| RAM (max) | 16 GB | 32 GB |
| Drive bays | 8 | 8 |
| Expandable to | 12 total with RX418 | 12 with RX418 |
| M.2 slots | 2 via optional M2D18 adapter; SATA only | 0; optional adapter card |
| Network | 4 x 1GbE RJ-45 | 4× 1GbE RJ-45 |
| 10GbE | optional | optional |
| Max raw capacity | 144 TB with RX418 | 108 TB single volume |
| Hot-swap | yes | yes |
| Form factor | 2U rackmount | 2U rackmount |
| Released | 2018 | 2020 |
| Power consumption | 60.31 W / 29.04 W | 61.94 W / 29.98 W |
| DSM at launch | — | — |
Choose the RS1221RP+ if you want the stronger CPU (AMD Ryzen class vs older Intel Celeron), much higher RAM ceiling, and the ability to add 10GbE and M.2 cache/SSD options; it also has the redundant PSU model (“RP”) for better uptime. The RS1219+ is the simpler, lower-power choice, but it’s weaker on performance and expandability: lower RAM ceiling, no built-in/official M.2 support, and fewer upgrade headroom options. Both are 4-bay units with Synology expansion support, but the RS1221RP+ is the better pick for performance and future-proofing.