Main trade-off
Synology DiskStation DS925+
Included network ports are limited to 2.5GbE per link.
Head-to-head
Synology DS925+ vs TerraMaster F4-425 Plus: Same starting HDD capacity, Synology has a separate bay expansion path
The short answer
Choose DS925+ when Synology's documented DX525 expansion route and ECC memory fit a growing archive. Choose F4-425 Plus when dual 5GbE, three M.2 slots and 16GB supplied memory solve the current workstation setup. Both begin with four SATA bays, so identical drive and RAID choices do not produce different protected capacity merely because the brands differ.
Before you choose
The reasoning and the trade-offs
Four equal drives give the same starting storage arithmetic
With four equal 8TB drives, RAID 5 provides about 24TB before overhead on either model. RAID 6 instead leaves about 16TB while tolerating two drive failures.
What this is based on
Four-drive RAID 5 uses (4 minus 1) × 8TB. RAID 6 uses (4 minus 2) × 8TB. Capacity examples exclude formatting, system space and retained versions.
Main trade-off
TerraMaster F4-425 Plus N150 16GB
The third M.2 slot does not add another SATA archive bay.
DS925+ shown with optional DX525 expansion unit. DX525 and drives are sold separately.
Synology DiskStation DS925+
- Choose it for
- Add a supported DX525 when more SATA bays are needed
- Use a system supplied with ECC memory
- Main trade-off
- Included network ports are limited to 2.5GbE per link.
TerraMaster F4-425 Plus N150 16GB
- Choose it for
- Use included 5GbE links and three M.2 slots
- Start with the selected 16GB N150 configuration
- Main trade-off
- The third M.2 slot does not add another SATA archive bay.
About this comparison
Compare DS925+ and the N150 F4-425 Plus for four-drive backup storage, future SATA expansion and a workstation using 5GbE.
Choose DS925+ when Synology's documented DX525 expansion route and ECC memory fit a growing archive. Choose F4-425 Plus when dual 5GbE, three M.2 slots and 16GB supplied memory solve the current workstation setup. Both begin with four SATA bays, so identical drive and RAID choices do not produce different protected capacity merely because the brands differ.
Winner by situation
Start with what you need it to do
Need one included 5GbE workstation connection
DS925+ ports negotiate up to 2.5GbE. TerraMaster includes 5GbE.
- Synology DiskStation DS925+
- Caution
- TerraMaster F4-425 Plus N150 16GB
- Better fit
Plan a supported DX525 SATA expansion
DX525 is the documented Synology-specific expansion route.
- Synology DiskStation DS925+
- Better fit
- TerraMaster F4-425 Plus N150 16GB
- Not suitable
Require ECC memory
Synology explicitly supplies DDR4 ECC. The TerraMaster listing does not establish equivalent system ECC.
- Synology DiskStation DS925+
- Better fit
- TerraMaster F4-425 Plus N150 16GB
- Caution
Install a 16GB supplied-memory configuration
TerraMaster supplies 16GB. DS925+ supplies 4GB and needs an upgrade for that quantity.
- Synology DiskStation DS925+
- Caution
- TerraMaster F4-425 Plus N150 16GB
- Better fit
What matters in practice
The differences that matter
Four equal drives give the same starting storage arithmetic
With four equal 8TB drives, RAID 5 provides about 24TB before overhead on either model. RAID 6 instead leaves about 16TB while tolerating two drive failures.
How we reached this conclusion
Four-drive RAID 5 uses (4 minus 1) × 8TB. RAID 6 uses (4 minus 2) × 8TB. Capacity examples exclude formatting, system space and retained versions.
A faster workstation needs a faster path all the way through
F4-425 Plus includes 5GbE sockets, while DS925+ includes 2.5GbE sockets. Choose TerraMaster if a single 5GbE client path is already planned and the storage workload benefits from removing that link-rate ceiling.
How we reached this conclusion
The comparison concerns one Ethernet connection. Adding the two 2.5GbE ratings does not create a single 5GbE connection without a separately supported multichannel setup.
Do not turn the RAM label into a reliability or speed promise
DS925+ supplies 4GB ECC memory. This F4-425 Plus listing supplies 16GB DDR5.
How we reached this conclusion
Supplied memory differs in both quantity and type. The TerraMaster listing must remain the N150 16GB variant, not a different selectable configuration.
Choice A
DS925+ shown with optional DX525 expansion unit. DX525 and drives are sold separately.
Synology, DS925+
Synology DiskStation DS925+
The chassis has 4-bay storage. Its fastest documented network path is 2.5 Gbps.
- Best matched use
- Add a supported DX525 when more SATA bays are needed
Checked facts
- Internal SATA bays: Four
- Included Ethernet: Two 2.5GbE ports
- Supplied memory: 4GB DDR4 ECC
- M.2 slots: Two
Choice B
TerraMaster, F4-425 Plus N150 16GB
F4-425 Plus N150 16GB
Four SATA bays, three M.2 slots and 16GB supplied memory make room for a bulk array and SSD-backed applications. Dual 5GbE ports suit an upgraded home or small-office network.
- Best matched use
- Use included 5GbE links and three M.2 slots
Checked facts
- Internal SATA bays: Four
- Included Ethernet: Two 5GbE ports
- Supplied memory: 16GB DDR5
- M.2 slots: Three
Meaningful differences
What changes the fit
| What changes | Synology DiskStation DS925+ | TerraMaster F4-425 Plus N150 16GB | Why it matters |
|---|---|---|---|
| Internal SATA bays | Four | Four | The same equal-drive RAID layout starts with the same nominal capacity. |
| Included Ethernet | Two 2.5GbE ports | Two 5GbE ports | A single 5GbE workstation link favors TerraMaster. |
| Supplied memory | 4GB DDR4 ECC | 16GB DDR5 | Memory quantity and error correction are different attributes. |
| M.2 slots | Two | Three | One extra onboard SSD slot remains after a two-SSD mirror on TerraMaster. |
| SATA expansion plan | One DX525 supports nine bays in total | Four internal SATA bays, separate USB DAS options require their own plan | Synology documents a specific five-bay expansion accessory. |
What you give up
Every choice has a cost
If you choose Synology DiskStation DS925+
- Reaching a 16GB memory plan requires an additional purchase.
If you choose TerraMaster F4-425 Plus N150 16GB
- A separate USB enclosure is not automatically equivalent to Synology's DX525 integration.
Recommendation switch
The decision flips if...
The archive must grow through a supported DX525
Choose Synology DiskStation DS925+. DS925+ supports that named expansion unit.
The immediate setup needs 5GbE and 16GB supplied memory
Choose TerraMaster F4-425 Plus N150 16GB. The selected N150 F4-425 Plus includes both.
What matters in practice
How to make the call
Four equal drives give the same starting storage arithmetic
With four equal 8TB drives, RAID 5 provides about 24TB before overhead on either model. RAID 6 instead leaves about 16TB while tolerating two drive failures. Choose between these chassis for the surrounding workflow, not a claim that faster networking creates more protected space. If that archive is likely to outgrow four drives, DS925+'s supported DX525 route deserves budgeting before the first pool is filled.
A faster workstation needs a faster path all the way through
F4-425 Plus includes 5GbE sockets, while DS925+ includes 2.5GbE sockets. Choose TerraMaster if a single 5GbE client path is already planned and the storage workload benefits from removing that link-rate ceiling. A Gigabit switch or adapter still limits either NAS on that leg. DS925+ remains a sensible option when its storage expansion and DSM workflow matter more than a faster included port.
Do not turn the RAM label into a reliability or speed promise
DS925+ supplies 4GB ECC memory. This F4-425 Plus listing supplies 16GB DDR5. Choose Synology if ECC is an explicit hardware requirement, or TerraMaster if a documented application plan needs more than 4GB at installation. Neither label proves application capacity or overall data safety. Backups remain necessary, and any later memory purchase should use the manufacturer's approved configuration.
What this comparison cannot tell you
- No comparative reliability, application speed or transcoding test is claimed. ECC memory does not replace backups.
What the facts say
What the comparison shows
Useful conclusions from the current NAS devices comparison, followed by the checked facts used to reach them.
See the checked facts and calculation notes
| Product | Needs matched | Checked facts | Source records |
|---|---|---|---|
| Synology DiskStation DS925+ |
|
| |
| TerraMaster F4-425 Plus N150 16GB |
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|
Ready to choose?
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DS925+ shown with optional DX525 expansion unit. DX525 and drives are sold separately.
Synology DiskStation DS925+
Add a supported DX525 when more SATA bays are needed
See price & reviews on AmazonTerraMaster F4-425 Plus N150 16GB
Use included 5GbE links and three M.2 slots
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