Side-by-side specifications of the Synology DS1621+ and DS1812+, from official datasheets. Differences are highlighted.
| DS1621+ | DS1812+ | |
| CPU | AMD Ryzen V1500B, 2.2 GHz | Dual Core 2.13 GHz |
| Cores / threads | 4 cores / 8 threads | 2 cores / 2 threads |
| RAM (base) | 4 GB DDR4 ECC SODIMM | 1 GB |
| RAM (max) | 32 GB (16 GB x 2) | 3 GB |
| Drive bays | 6 | 8 |
| Expandable to | 16 total with 2 DX517 units | 10 |
| M.2 slots | 2 x M.2 2280 NVMe | 0 |
| Network | 4 x 1GbE RJ-45 | 2x Gigabit |
| 10GbE | optional | no |
| Max raw capacity | 256 TB raw with 2 DX517 units | 54 TB |
| Hot-swap | yes | yes |
| Form factor | desktop | Desktop |
| Released | 2020 | 2012 |
| Power consumption | 51.22 W / 25.27 W | 71.5 W / 28.6 W |
| DSM at launch | — | — |
Choose the DS1621+ for its much newer Ryzen V1500B CPU, 4 GB ECC RAM expandable to 32 GB, six bays plus eSATA expansion, optional 10GbE, and dual M.2 NVMe slots. The DS1812+ has eight bays and eSATA expansion but an older Atom D2700, a 3 GB RAM ceiling, no native 10GbE option, and no M.2 support.