Upgrade the Memory in the DS225+ and DS425+
2GB fitted, one slot, 6GB limit, non-ECC DDR4 SO-DIMM
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The DS225+ and DS425+ use the same memory design: DDR4 non-ECC SO-DIMM, one slot, to a limit of 6 GB (2 GB + 4 GB). Both ship with 2GB. So the only upgrade is one 4GB module, the D4NS01-4G on Synology's list, taking either from 2GB to 6GB.
Memory facts for the DS225+ and DS425+
| DS225+ | DS425+ | |
|---|---|---|
| Fitted | 2 GB DDR4 non-ECC | 2 GB DDR4 non-ECC |
| Slots | 1 | 1 |
| Limit | 6 GB (2 GB + 4 GB) | 6 GB (2 GB + 4 GB) |
| Modules Synology lists | D4NS01-4G | D4NS01-4G |
| Processor | Intel Celeron J4125, 4 cores | Intel Celeron J4125, 4 cores |
| Largest single volume | 108TB | 108TB |
One slot, one decision
With 2GB fitted and one slot, the DS225+ and DS425+ go to 6GB with a single 4GB module and no further. Synology writes the limit as 6 GB (2 GB + 4 GB). If you need more than 6GB, the answer is a different model, not a different module.
Whether 6GB is enough depends on what you run. It is a file-server amount of memory; the Ryzen models in the same 2025 range reach 32GB.
Where the memory figures come from
Fitted memory, slot count, limit and the listed modules are from Synology's specification pages for these models, read on October 12, 2026. Synology validates only its own modules; it does not publish a list of third-party modules, so none is named here.
Checked on October 12, 2026. Sources: Synology DS225+ technical specifications; Synology DS425+ technical specifications.
Background this page does not repeat
Only DS225+ and DS425+ specifics are on this page.
NAS drive basics: CMR, NAS-rated drives and SHR · Synology DSM 7.3 third-party drive policy
DDR4 non-ECC SO-DIMM modules up to 4GB, by price
Non-ECC DDR4 SO-DIMM modules of 4GB or smaller: the right type and size, not modules Synology has validated. Synology validates only its own.
Frequently asked questions
How much RAM can the DS225+ and DS425+ take?
6 GB (2 GB + 4 GB), on both.
Which modules does Synology list for the DS225+ and DS425+?
DDR4 non-ECC SO-DIMM: the D4NS01-4G.
How much memory do the DS225+ and DS425+ come with?
2 GB DDR4 non-ECC, with one memory slot and a limit of 6 GB (2 GB + 4 GB).
Is the memory in the DS225+ and DS425+ ECC?
No. Both ship with non-ECC memory and the listed module, the D4NS01-4G, is non-ECC.