Synology DS1525+: Specs, Drive Compatibility and Total Build Cost
The DS1525+ is Synology's 5-bay Plus-series DiskStation, sitting between the mainstream 4-bay DS925+ and the 8-bay DS1825+ in the same generation. Below is what Synology's own spec sheet states, what it costs filled with drives today, and its drive-compatibility position.
Hardware specifications, per Synology's own spec sheet
| Bays | 5 |
|---|---|
| Drive form factors | 5 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; optional 10GbE upgrade module (E10G22-T1-Mini) via a PCIe Gen3 x2 slot, sold separately |
| Expansion unit | DX525 (up to 2 units) - 15 total bays |
| PSU | 120W |
| Published acoustic figure | 22.6 dB(A), Synology's own stated test method (idle, fully populated, 1m) |
Source: Synology DS1525+ Product Specification, read 2026-09-14 — PDF.
The honest total: chassis + drives, three ways
$1309.99 buys the empty chassis. Five bays filled is the real purchase, and the three tiers below are genuinely different builds, not three versions of the same one.
Best value fill - DS1525+ + 5 drives
Usable capacity by RAID level: RAID 1 20TB ($127.50/usable TB) · RAID 5 80TB ($31.87/usable TB) · RAID 6 60TB ($42.50/usable TB) 6 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) | x5 | $509.99 | $2549.95 | Buy |
| ChassisSynology DiskStation DS1525+ 5-Bay | x1 | $1309.99 | $1309.99 | Buy |
| Basket total | $3859.94 | |||
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 - DS1525+ + 5 drives
Usable capacity by RAID level: RAID 1 12TB ($137.50/usable TB) · RAID 5 48TB ($34.37/usable TB) · RAID 6 36TB ($45.83/usable TB) 6 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) | x5 | $329.99 | $1649.95 | Buy |
| ChassisSynology DiskStation DS1525+ 5-Bay | x1 | $1309.99 | $1309.99 | Buy |
| Basket total | $2959.94 | |||
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 - DS1525+ + 5 drives
Usable capacity by RAID level: RAID 1 2TB ($95.00/usable TB) · RAID 5 8TB ($23.75/usable TB) · RAID 6 6TB ($31.67/usable TB) 6 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) | x5 | $38.00 | $190.00 | Buy |
| ChassisSynology DiskStation DS1525+ 5-Bay | x1 | $1309.99 | $1309.99 | Buy |
| Basket total | $1499.99 | |||
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 5 bays, separately from the value tiers above: 5 x Toshiba MG03ACA200 2TB SATA Enterprise at $104.98 each = $524.90.
Drive compatibility, measured
At five bays the DS1525+ is where the arithmetic starts to bite. The same 22 listed hard drives apply as on the two-bay machines, but five drives bought together turns a per-terabyte preference into a three-figure decision, and that is before any of them is replaced.
At five bays the arithmetic bites harder than at four: 117 fit-verified third-party SATA HDDs are in our catalogue right now, none on Synology's own list, and five drives bought at a brand premium rather than one turns a per-terabyte preference into real money.
Full DS1525+ compatible-drives page and Synology's drive policy, per series, dated.
Expansion limits and the M.2 reality
DX525 (up to 2 units) - 15 total bays. Unlike the DS925+ below it in the range, the DS1525+ also documents a genuine networking upgrade path: a PCIe Gen3 x2 slot for Synology's own 10GbE module (E10G22-T1-Mini), sold separately - worth knowing if 2.5GbE is a limit you expect to hit.
The M.2 slots follow the same pattern as the rest of this Plus generation: Synology's own spec sheet lists both SSD read/write cache and an independent M.2 storage pool as supported, not cache-only - a real choice with a real footnote, since the storage-pool use case specifically requires Synology-verified SSDs.
Five bays is also the point where the RAID-level decision genuinely branches. Synology's SHR aside, standard RAID 5 needs at least three drives and RAID 6 needs at least four - five bays is the smallest count where choosing RAID 6 over RAID 5 costs only one additional drive of usable space rather than a proportionally larger bite, which is why the usable-capacity figures in the baskets above are worth reading by RAID level rather than assuming RAID 5 is the default at this size the way it might be at four bays.
What else it needs
Power protection: see UPS units for a NAS, priced live with output waveform stated on every row. If the optional 10GbE module is part of the plan, the switch on the other end needs to match it - see 10GbE for a NAS for what ships the port and the honest case for staying on 2.5GbE instead.
Frequently asked questions
Frequently asked questions
How many drives does the DS1525+ take?
5, 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 DS1525+?
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 15 total bays.
Can I use third-party drives in the DS1525+?
Yes. Synology's own list for the DS1525+ names 22 hard drives, all Synology's own HAT series - but the DS1525+ is a Plus-tier machine, and on that tier an unlisted hard drive still creates a storage pool, labelled Unverified in DSM rather than refused.
Does the DS1525+ support 10GbE?
Not standard - it ships with 2.5GbE, but Synology documents an optional 10GbE network upgrade module through a PCIe Gen3 x2 slot, sold separately. That is a real upgrade path the DS925+ below it in the line does not have.
What does a complete DS1525+ build cost?
$1309.99 for the chassis alone; $2549.95 filled with 5 best-value drives, or as little as $524.90 for the smallest qualifying set.
Why 5 bays specifically?
Five sits between the mainstream 4-bay and the larger 8-bay in the same Plus generation, and Synology prices and specs it as a distinct step rather than a 4-bay with one bay bolted on - same CPU-adjacent platform, same RAM ceiling, one more bay of RAID 5 or RAID 6 headroom.
Sources checked: Synology DS1525+ product page, Synology DS1525+ Product Specification (PDF), Synology compatibility search.