Written 22 Aug 2026. Specs from the maker pages linked below. Prices from those stores. I haven't used these. Confirm the diskless SKU before you click. Amazon is full of drive bundles.
Four-bay overnight backups on DSM when two bays are not enough: DS423+
Four-bay overnight backups on Synology DSM when two bays are not enough. Still gigabit. Same CPU as the DS224+.
Four-bay overnight backups on Synology DSM when two bays are not enough. If you already decided DSM, this is the growth box. It is not a used DS918+. It is not a 2.5G or 10G chassis. Same Intel Celeron J4125, same official 6 GB RAM lid (2 GB DDR4 plus one 4 GB SO-DIMM), same dual 1GbE with MTU 1500. What you get for the extra money is four hot-swap 3.5" / 2.5" SATA bays, two M.2 2280 NVMe slots (cache or pool), two 92 mm fans, and a 3-year warranty instead of two.
Official size 166 × 199 × 223 mm, 2.18 kg. 90 W brick. Spec PDF (last updated 23 Apr 2025) lists 28.30 W access and 8.45 W HDD hibernation, 19.8 dB(A) idle with Synology HDDs at 1 m. Scheduled power on/off is still there. RAID adds 5 / 6 / 10 on top of SHR / Basic / JBOD / 0 / 1. M.2 slots are not hot-swap. Creating an M.2 storage pool wants Synology-verified SSDs per the spec note.
Virtual Machine Manager is still “recommended 2 VMs.” Object recognition in Photos still wants 4 GB. The NIC does not grow. A single HDD RAID 1 or SHR pair still lives around 150–210 MB/s sequential; gigabit is the client lid, not the drives. Empty bays and M.2 cache are the reasons to pay for this over the DS224+, not “faster Ethernet.” Compare the two here: DS224+ vs DS423+.
Fill SATA with CMR NAS HDDs. WD Red Plus (CMR; 8 TB example WD80EFPX is 5640 RPM). IronWolf / IronWolf Pro (CMR, but IronWolf 1–6 TB is 5400 RPM; ST8000VN004 8 TB is 7200). Toshiba N300 (CMR). Skip WD Red EFAX, WD Blue 3.5" EZAZ, BarraCuda 3.5" 4 / 8 TB SMR. 5400 / 5640 RPM is fine for backups. Wrong as the only iSCSI datastore for VMs unless you put the VMs on the M.2 pool or a SATA SSD.
Street, 22 Aug 2026
| Path | Listing | Note |
|---|---|---|
| B&H diskless | $499.99 listed (research fetch, 22 Aug 2026). | 1757288-REG. Lead with this. A later Cloudflare wall blocked our re-fetch; confirm the live card. |
| Amazon diskless | ASIN B0BXMS9GFF exists | B0BXMS9GFF was out of stock at the 22 Aug 2026 research fetch. Don't substitute a 16 TB + RAM bundle (Newegg 14P-000V-004V2 class). |
Want 2.5G and four M.2 instead of DSM? AS5404T. Want four cheap bays and TOS? F4-425. Want 10G and Docker? That is the existing UGREEN DXP4800 Plus slot, not this page.
Skip
Skip if you need 2.5G or 10G today. There is no NIC upgrade. Skip a used DS918+ as a “cheaper 4-bay Plus”; that path is out. Skip SMR leftovers in SHR. Skip treating four 5400 RPM disks as a Proxmox datastore.
Sources
DS423+ product spec PDF (23 Apr 2025). Datasheet PDF. B&H 1757288-REG. Amazon B0BXMS9GFF. Android Central historical $514 Amazon / $499 B&H. Synology US product HTML did not render a clean product page on our 22 Aug 2026 fetch (download-center / catalog bounce).