Side-by-side specifications of the Synology DS1812+ and DS1821+, from official datasheets. Differences are highlighted.
| DS1812+ | DS1821+ | |
| CPU | Dual Core 2.13GHz | AMD Ryzen V1500B |
| Cores / threads | 2 | 4 |
| RAM (base) | 1 GB | 4 GB |
| RAM (max) | 3 GB | 32 GB |
| Drive bays | 8 | 8 |
| Expandable to | 18 | 18 |
| M.2 slots | 0 | 2 |
| Network | 2x Gigabit | 4x1GbE RJ-45 |
| 10GbE | no | optional |
| Max raw capacity | 54 TB | 108 TB |
| Hot-swap | yes | yes |
| Form factor | desktop | desktop |
| Released | 2012 | 2020 |