Main trade-off
ASUSTOR Nimbustor 4 Gen2
The extra hardware does not bring Synology's DSM applications.
Head-to-head
ASUSTOR AS5404T vs Synology DS425+: Same hard-drive count, ASUSTOR leaves more NVMe and RAM room
The short answer
Choose AS5404T for four NVMe positions, more official RAM headroom and two 2.5GbE ports. Choose DS425+ if DSM photos and backup tools fit the way you manage files. Both hold four SATA drives, so the difference is the surrounding hardware and software, rather than basic hard-drive capacity.
Before you choose
The reasoning and the trade-offs
The same hard-drive array does not favor either chassis
Four compatible 12 TB hard drives in RAID 5 provide 36 TB before overhead on either model. Choosing ASUSTOR does not create extra hard-drive capacity, and choosing Synology does not reduce it for this equal-drive example.
What this is based on
(4 - 1) × 12 TB = 36 TB before formatting and system overhead. Both models have four SATA bays and support RAID 5.
Main trade-off
Synology DiskStation DS425+
Two NVMe slots and 6 GB official RAM maximum.
ASUSTOR Nimbustor 4 Gen2
- Choose it for
- Keep four hard drives and plan several NVMe devices
- Allow up to 16 GB of supported memory for home applications
- Main trade-off
- The extra hardware does not bring Synology's DSM applications.
Synology DiskStation DS425+
- Choose it for
- Use DSM for photos, shared files and backups
- Build a four-drive array within Synology's supported storage workflow
- Main trade-off
- Two NVMe slots and 6 GB official RAM maximum.
About this comparison
ASUSTOR AS5404T vs Synology DS425+ for a four-drive NAS. Compare NVMe layouts, memory headroom, network ports and the real cost of the SSD plan.
Choose AS5404T for four NVMe positions, more official RAM headroom and two 2.5GbE ports. Choose DS425+ if DSM photos and backup tools fit the way you manage files. Both hold four SATA drives, so the difference is the surrounding hardware and software, rather than basic hard-drive capacity.
Winner by situation
Start with what you need it to do
I want four hard drives in RAID 5
Both support the same basic four-drive layout.
- ASUSTOR Nimbustor 4 Gen2
- Good
- Synology DiskStation DS425+
- Good
I need four NVMe positions
ASUSTOR provides four slots and Synology provides two.
- ASUSTOR Nimbustor 4 Gen2
- Better fit
- Synology DiskStation DS425+
- Not suitable
My selected applications need 8 GB RAM
ASUSTOR supports up to 16 GB. Synology's official ceiling is 6 GB.
- ASUSTOR Nimbustor 4 Gen2
- Depends
- Synology DiskStation DS425+
- Not suitable
I specifically want Synology's photo and backup software
DS425+ provides DSM and its associated packages. Check each package requirement.
- ASUSTOR Nimbustor 4 Gen2
- Not suitable
- Synology DiskStation DS425+
- Better fit
What matters in practice
The differences that matter
The same hard-drive array does not favor either chassis
Four compatible 12 TB hard drives in RAID 5 provide 36 TB before overhead on either model. Choosing ASUSTOR does not create extra hard-drive capacity, and choosing Synology does not reduce it for this equal-drive example.
How we reached this conclusion
(4 - 1) × 12 TB = 36 TB before formatting and system overhead. Both models have four SATA bays and support RAID 5.
Two separate mirrored NVMe pairs need four positions
A plan with one two-SSD mirror for applications and another two-SSD mirror for a separate workload needs four NVMe slots. AS5404T has the physical positions. DS425+ has only two, so it cannot build that exact all-NVMe layout internally.
How we reached this conclusion
2 drives in the first mirror + 2 drives in the second = 4 NVMe positions. AS5404T has 4 and DS425+ has 2. Software and compatible drives still need checking.
The cabinet shape changes a narrow-shelf decision
AS5404T is 25 mm narrower than DS425+ but 7 mm deeper. A tight side-by-side shelf may favor ASUSTOR, while a shallow cabinet may favor Synology. Neither dimension comparison includes cable and ventilation clearance.
How we reached this conclusion
199 - 174 = 25 mm width difference. 230 - 223 = 7 mm depth difference.
Choice A
ASUSTOR, AS5404T
ASUSTOR Nimbustor 4 Gen2
The chassis has 4-bay storage. Its fastest documented network path is 2.5 Gbps.
- Best matched use
- Keep four hard drives and plan several NVMe devices
Checked facts
- SATA drive positions: 4
- M.2 NVMe slots: 4
- Installed / maximum memory: 4 GB / 16 GB
- Ethernet ports: Two 2.5GbE
Choice B
Synology, DS425+
Synology DiskStation DS425+
The chassis has 4-bay storage. Its fastest documented network path is 2.5 Gbps.
- Best matched use
- Use DSM for photos, shared files and backups
Checked facts
- SATA drive positions: 4
- M.2 NVMe slots: 2
- Installed / maximum memory: 2 GB / 6 GB
- Ethernet ports: One 2.5GbE and one 1GbE
Meaningful differences
What changes the fit
| What changes | ASUSTOR Nimbustor 4 Gen2 | Synology DiskStation DS425+ | Why it matters |
|---|---|---|---|
| SATA drive positions | 4 | 4 | The same equal-drive RAID layout has the same nominal capacity arithmetic. |
| M.2 NVMe slots | 4 | 2 | ASUSTOR has two more physical NVMe positions. |
| Installed / maximum memory | 4 GB / 16 GB | 2 GB / 6 GB | Compare the requirements of the actual apps, not just the maximum number. |
| Ethernet ports | Two 2.5GbE | One 2.5GbE and one 1GbE | Each supports one 2.5GbE link. Additional links require a suitable network configuration. |
| NVMe storage planning | Compatible NVMe storage or caching | Storage pools require Synology-verified SSDs | The physical slot does not establish support for any SSD you already own. |
| Case width and depth | 174 × 230 mm | 199 × 223 mm | ASUSTOR is narrower, while Synology is slightly shallower. |
What you give up
Every choice has a cost
If you choose ASUSTOR Nimbustor 4 Gen2
- NVMe and RAM upgrades add to the diskless enclosure price.
If you choose Synology DiskStation DS425+
- M.2 storage pools require Synology-verified SSDs.
Recommendation switch
The decision flips if...
My plan requires four internal NVMe devices
Choose ASUSTOR Nimbustor 4 Gen2. Only AS5404T has four M.2 slots.
DSM is the software environment I want
Choose Synology DiskStation DS425+. DS425+ provides the Synology workflow with four SATA bays.
What matters in practice
How to make the call
Choose the software before filling the extra slots
Four hard-drive bays cover the same basic storage layouts on both models. The extra ASUSTOR NVMe slots and memory support matter when a specific workload needs them. If you mainly want DSM's photo organization and backup routine, unused hardware capacity elsewhere may be less important than that daily workflow.
Price the SSDs that the platform actually supports
Synology's current specifications allow M.2 storage pools, with a requirement for Synology-verified SSDs. It would be wrong to describe those slots as cache-only, or to assume any spare NVMe drive is supported. Check the exact drive and firmware before building the budget around an SSD already in a drawer.
Two Ethernet ports do not automatically combine for one transfer
ASUSTOR has two 2.5GbE ports, while Synology mixes 2.5GbE and 1GbE. Both can connect a suitable client through one 2.5GbE path. Using multiple links effectively depends on the protocol, client and network setup. Do not add the port labels together and treat the result as a guaranteed copy speed.
What this comparison cannot tell you
- Storage calculations use equal-capacity compatible drives and decimal TB before formatting, system space and metadata. RAID protects against specified drive failures but does not replace a separate backup.
- Network figures are link rates rather than measured file-transfer speeds. Software support, memory revision, drive compatibility and the rest of the network must be checked for the exact purchase.
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 |
|---|---|---|---|
| ASUSTOR Nimbustor 4 Gen2 |
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| Synology DiskStation DS425+ |
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Ready to choose?
Check the price. Read the owner reviews.
Open either model on Amazon to check the current price, customer reviews and delivery options.
ASUSTOR Nimbustor 4 Gen2
Keep four hard drives and plan several NVMe devices
See price & reviews on AmazonSynology DiskStation DS425+
Use DSM for photos, shared files and backups
See price & reviews on AmazonLinks open in a new tab.