Best M.2 NVMe for the Synology DiskStation DS423+
By Devin Chua · Data checked by Owen Nakamura · Updated The Synology DiskStation DS423+ has 2 M.2 slots. The catch most guides miss: for NVMe, Synology still requires a drive from its own list (SNV3400 or SNV5400), and the DSM 7.3 relaxation did not change that — it covered hard drives and SATA SSDs only. So on the DS423+, a Samsung 990 will not do. Whether a cache pays off depends on the 2 × 1GbE link and on whether you re-read the same data — for a media library streamed once, it does not.
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M.2 NVMe for the DS423+, live from Amazon.ca
What sets the DS423+ apart
The price entry with four bays and SHR. The Celeron J4125 can transcode Plex with hardware acceleration, but the 2 GB of RAM out of the box is tight: the single free SO-DIMM is effectively mandatory and caps you at 6 GB.
Cache or a fast pool on the DS423+?
The DS423+'s 2 M.2 slots (2 × m.2 nvme for cache; an nvme storage pool requires a synology drive) can serve as a read cache or, depending on the OS, as their own fast storage pool. A cache only speeds up data you read more than once: on the DS423+, a media library streamed through once gains nothing, while repeated project files, photo libraries or container images show the difference immediately. Weigh that against its 2 × 1GbE link, which is often the real limit.
On the DS423+ an NVMe storage pool is possible, but only with Synology's own SNV3400 or SNV5400 — the DSM 7.3 relaxation did not reach M.2, so this is the one place the DS423+ still enforces a drive list. Budget for that when you plan a cache.
The Synology drive policy on the DS423+
unrestrictedOpen. The 2025 restriction does not apply retroactively; every NAS drive works.
The DS423+ at a glance
| Bays | 4 × 3.5-inch SATA and 2.5-inch SATA SSD |
|---|---|
| Maximum raw capacity | 96 TB 4 × 24 TB: the largest drive on Synology's list for this model. The often-quoted 108 TB is the maximum volume size, not the sum of drives. |
| Processor | Intel Celeron J4125 (4 cores) |
| Memory | 2 GB, DDR4 SO-DIMM, no ECC (2 GB soldered plus 1 slot) 6 GB official (2 GB fixed plus a 4 GB module). In practice a 16 GB module runs (giving 18 GB); Synology does not endorse it. |
| M.2 NVMe | 2 slots 2 × M.2 NVMe for cache; an NVMe storage pool requires a Synology drive |
| Network | 2 × 1GbE |
| Operating system | DSM 7.x |
| RAID types | SHR, SHR-2, Basic, JBOD, RAID 0, RAID 1, RAID 5, RAID 6, RAID 10 SHR also makes use of mixed drive sizes. |
Keep calculating
To see how much capacity is left after parity, the DS423+ capacity calculator is preset to its 4 bays and RAID types. For the DS423+, the wider basics of choosing a drive are in the buying guides, where we also explain why CMR rather than SMR is mandatory in any RAID array.
Frequently asked questions
How many M.2 slots does the DS423+ have?
2. 2 × M.2 NVMe for cache; an NVMe storage pool requires a Synology drive
Is an NVMe cache worth it in the DS423+?
Only if you re-read the same data on the DS423+: project files, photos, container images. A media library streamed once gains nothing, and with 2 × 1GbE the link is often the limit before the drive is.
Can I put any NVMe in the DS423+?
No. On the DS423+, Synology still requires an SNV3400 or SNV5400 for both cache and an NVMe pool — the DSM 7.3 drive-policy relaxation of 8 October 2025 covered hard drives and SATA SSDs, not M.2.
Can I put third-party drives in the DS423+?
Yes, without restriction. The 2025 Synology drive lock covers only the 2025 models, so the DS423+ takes any NAS drive and has always done so.
Devin Chua works out which drives, RAM and NVMe cache fit which NAS model at nasdrives.ca, and what the RAID choice means for usable capacity, checked against what is in stock on Amazon.ca.
Data checked by Owen Nakamura, Technical editor (data checking)