Side-by-side specifications of the Synology RS818+ and RS818RP+, from official datasheets. Differences are highlighted.
| RS818+ | RS818RP+ | |
| CPU | Intel Atom C2538 | Intel Atom C2538 |
| Cores / threads | 4-core | 4-core |
| RAM (base) | 2 GB | 2 GB |
| RAM (max) | 16 GB | 16 GB |
| Drive bays | 4 | 4 |
| Expandable to | 8 | 8 |
| M.2 slots | 0 | 0 |
| Network | 4 x 1GbE | 4 x 1GbE |
| 10GbE | optional | optional |
| Max raw capacity | 80 TB | 80 TB |
| Hot-swap | yes | yes |
| Form factor | 1U rackmount | 1U |
| Released | 2017 | 2018 |
Pick the RS818RP+ only if you need redundant power supplies; otherwise the RS818+ is usually the better value. Both use the same CPU class (Intel Atom C2538), have 4 bays and no native M.2 support, and can be expanded with the same 8-bay RX418; neither has built-in 10GbE. The main practical difference is memory headroom: RS818RP+ tops out at 16GB ECC, while RS818+ supports up to 2GB stock unless you’re using a different hardware revision—so verify the exact unit before buying.