Synology DS1825+: Specs, Drive Compatibility and Total Build Cost
The DS1825+ is Synology's 8-bay Plus-series DiskStation, and the top of the desktop range this cluster tracks. Below is what Synology's own spec sheet states, what it costs filled with drives at today's prices, and its drive-compatibility position.
Hardware specifications, per Synology's own spec sheet
| Bays | 8 |
|---|---|
| Drive form factors | 8 x 3.5-inch SATA HDD or 2.5-inch SATA SSD |
| M.2 slots | 2 x M.2 2280 NVMe |
| M.2 purpose | SSD cache OR an independent M.2 storage pool |
| Max single-drive capacity | not published by Synology |
| RAM | DDR4 ECC SODIMM, 8GB installed (1 slot used of 2) |
| Network | 2 x 2.5GbE RJ-45 built in; PCIe Gen3 x8 slot documented to support Synology's own 25GbE (E25G30-F2) or 10GbE (E10G30-F2/T2/T1) cards, sold separately |
| Expansion unit | DX525 (up to 2 units) - 18 total bays |
| PSU | 250W |
| Published acoustic figure | 23.8 dB(A), Synology's own stated test method (idle, fully populated, 1m) |
Source: Synology DS1825+ Product Specification, read 2026-09-14 — PDF.
The honest total: chassis + drives, three ways
$1367.99 buys the empty chassis. Eight bays filled is the real purchase, and at this bay count the gap between the three tiers below is the widest in this Synology line.
Best value fill - DS1825+ + 8 drives
Usable capacity by RAID level: RAID 1 20TB ($204.00/usable TB) · RAID 5 140TB ($29.14/usable TB) · RAID 6 120TB ($34.00/usable TB) · RAID 10 80TB ($51.00/usable TB) 9 items across 2 listings. In-stock listings only. Anything out of stock when this page loaded is named below rather than silently dropped.
| Item | Qty | Each | Line | |
|---|---|---|---|---|
| DriveMDD 20TB SATA 7200RPM NAS (20TB) | x8 | $509.99 | $4079.92 | Buy |
| ChassisSynology DiskStation DS1825+ 8-Bay | x1 | $1367.99 | $1367.99 | Buy |
| Basket total | $5447.91 | |||
These are our current tracked prices. Amazon sets the seller and the final price at checkout - verify before you buy. Opening any item starts an Amazon session, and anything you add there is part of the same order - you do not need to come back here between items.
Enterprise fill - DS1825+ + 8 drives
Usable capacity by RAID level: RAID 1 12TB ($219.99/usable TB) · RAID 5 84TB ($31.43/usable TB) · RAID 6 72TB ($36.67/usable TB) · RAID 10 48TB ($55.00/usable TB) 9 items across 2 listings. In-stock listings only. Anything out of stock when this page loaded is named below rather than silently dropped.
| Item | Qty | Each | Line | |
|---|---|---|---|---|
| DriveWD Ultrastar 12TB SATA HUH721212ALE601 (12TB) | x8 | $329.99 | $2639.92 | Buy |
| ChassisSynology DiskStation DS1825+ 8-Bay | x1 | $1367.99 | $1367.99 | Buy |
| Basket total | $4007.91 | |||
These are our current tracked prices. Amazon sets the seller and the final price at checkout - verify before you buy. Opening any item starts an Amazon session, and anything you add there is part of the same order - you do not need to come back here between items.
Refurbished fill - DS1825+ + 8 drives
Usable capacity by RAID level: RAID 1 2TB ($152.00/usable TB) · RAID 5 14TB ($21.71/usable TB) · RAID 6 12TB ($25.33/usable TB) · RAID 10 8TB ($38.00/usable TB) 9 items across 2 listings. In-stock listings only. Anything out of stock when this page loaded is named below rather than silently dropped.
| Item | Qty | Each | Line | |
|---|---|---|---|---|
| DriveToshiba MG03ACA200 2TB SATA Enterprise (2TB) | x8 | $38.00 | $304.00 | Buy |
| ChassisSynology DiskStation DS1825+ 8-Bay | x1 | $1367.99 | $1367.99 | Buy |
| Basket total | $1671.99 | |||
These are our current tracked prices. Amazon sets the seller and the final price at checkout - verify before you buy. Opening any item starts an Amazon session, and anything you add there is part of the same order - you do not need to come back here between items.
The smallest cheque that fills all 8 bays, separately from the value tiers above: 8 x Toshiba MG03ACA200 2TB SATA Enterprise at $104.98 each = $839.84.
Drive compatibility, measured
Eight bays makes the DS1825+ the machine where drive choice costs the most in absolute terms. It carries exactly the list the two-bay DS225+ does, which is the clearest evidence on this page that Synology's list tracks its own product range rather than any property of the chassis.
117 fit-verified third-party SATA HDDs are in our catalogue right now for this bay class, none on Synology's own list. At eight bays a per-terabyte brand preference compounds the most of any machine in this line.
Full DS1825+ compatible-drives page and Synology's drive policy, per series, dated.
Expansion limits and the M.2 reality
DX525 (up to 2 units) - 18 total bays. The DS1825+ is also the one model in this Synology line with a documented path past 10GbE: its PCIe Gen3 x8 slot supports Synology's own 25GbE card (E25G30-F2) as well as 10GbE cards, sold separately - neither the DS925+ nor the DS1525+ in the same generation document a 25GbE option.
The M.2 slots follow the rest of the Plus generation: both SSD read/write cache and an independent M.2 storage pool are supported, not cache-only, with Synology-verified SSDs required specifically for the storage-pool path per Synology's own footnote.
Eight bays is also where the RAID 5 versus RAID 6 gap is largest in absolute terms among the models this cluster tracks. RAID 5 across eight drives loses one drive of capacity to parity; RAID 6 loses two, and gains tolerance for a second drive failing during what is, at today's large drive sizes, a rebuild window measured in the better part of a day. The usable-capacity figures in the baskets above show both levels side by side rather than defaulting to one - at this bay count the choice is a real trade-off, not a formality.
What else it needs
Power protection: eight drives is enough that a UPS stops being optional - see UPS units for a NAS, priced live with output waveform stated. If a 10GbE or 25GbE card goes in the PCIe slot, the switch and cabling on the other end need to match it - see 25/40/100GbE hub and 10GbE for a NAS for live card, cable and switch prices.
Frequently asked questions
Frequently asked questions
How many drives does the DS1825+ take?
8, all 3.5-inch SATA HDD or 2.5-inch SATA SSD bays per Synology's own spec sheet, plus two M.2 2280 NVMe slots for cache or an independent storage pool.
What's the maximum capacity of the DS1825+?
Synology's own spec sheet publishes no maximum single-drive capacity for this model. With the DX525 expansion unit (up to two units), Synology documents 18 total bays.
Can I use third-party drives in the DS1825+?
Yes. Synology's own list for the DS1825+ names 22 hard drives, all Synology's own HAT series - but the DS1825+ is a Plus-tier machine, and an unlisted hard drive still creates a storage pool on it, labelled Unverified in DSM rather than refused.
Does the DS1825+ support 25GbE?
Documented, not standard. Synology lists a PCIe Gen3 x8 slot for this model that supports its own 25GbE card (E25G30-F2) or 10GbE cards (E10G30-F2/T2/T1), sold separately - the only model in Synology's current desktop DiskStation range we found with a documented 25GbE option at all.
What does a complete DS1825+ build cost?
$1367.99 for the chassis alone; $4079.92 filled with 8 best-value drives, or as little as $839.84 for the smallest qualifying set.
Why does the DS1825+ have a bigger power supply than the smaller models?
Synology documents a 250W supply for this model, against 100W on the 4-bay DS925+ and 120W on the 5-bay DS1525+ - eight spinning drives plus PCIe card headroom draws more than four or five, and Synology's own spec sheet sizes the PSU accordingly.
Sources checked: Synology DS1825+ product page, Synology DS1825+ Product Specification (PDF), Synology compatibility search.