The catch
ASUSTOR Nimbustor 4 Gen2
Synology's DSM applications do not come with the extra hardware.
Side by side
ASUSTOR AS5404T vs Synology DS425+ Compared: The hard-drive count matches, and ASUSTOR has more NVMe and RAM room
Quick verdict
Four NVMe positions, more official RAM headroom and two 2.5GbE ports favor the AS5404T. The DS425+ is the choice if DSM photos and backup tools suit how you manage files. Four SATA drives fit in both, so basic hard-drive capacity is equal. The surrounding hardware and software separate them.
Before you buy
Why, and what it costs you
Neither chassis is favored by the same hard-drive array
On either model, RAID 5 over four compatible 12 TB hard drives gives 36 TB before overhead. In this equal-drive example, picking ASUSTOR creates no extra hard-drive capacity and picking Synology takes none away.
Where this comes from
(4 - 1) × 12 TB = 36 TB before formatting and system overhead. Four SATA bays and RAID 5 support are common to both models.
The catch
Synology DiskStation DS425+
Just two NVMe slots, and an official RAM maximum of 6 GB.
ASUSTOR Nimbustor 4 Gen2
- Why pick it
- Run four hard drives and several NVMe devices together
- Plan for up to 16 GB of supported memory to run home applications
- The catch
- Synology's DSM applications do not come with the extra hardware.
Synology DiskStation DS425+
- Why pick it
- Run photos, shared files and backups through DSM
- Create a four-drive array that stays within what Synology's storage workflow supports
- The catch
- Just two NVMe slots, and an official RAM maximum of 6 GB.
We may earn a commission from qualifying Amazon purchases. How we make money
What this page compares
Four-drive NAS options, ASUSTOR AS5404T vs Synology DS425+, compared on NVMe layouts, memory headroom, network ports and the real cost of the SSD plan.
Four NVMe positions, more official RAM headroom and two 2.5GbE ports favor the AS5404T. The DS425+ is the choice if DSM photos and backup tools suit how you manage files. Four SATA drives fit in both, so basic hard-drive capacity is equal. The surrounding hardware and software separate them.
Which one fits
Pick the situations that sound like you
I plan to run four hard drives in RAID 5
The same basic four-drive layout works on both.
- ASUSTOR Nimbustor 4 Gen2
- Good
- Synology DiskStation DS425+
- Good
I require four NVMe positions
Four slots come with ASUSTOR, against two with Synology.
- ASUSTOR Nimbustor 4 Gen2
- Better fit
- Synology DiskStation DS425+
- Not suitable
The applications I selected need 8 GB RAM
Support goes up to 16 GB on ASUSTOR, while Synology's official ceiling is 6 GB.
- ASUSTOR Nimbustor 4 Gen2
- Depends
- Synology DiskStation DS425+
- Not suitable
Synology's photo and backup software is what I specifically want
DSM and its associated packages come with DS425+. Check the requirement of each package.
- ASUSTOR Nimbustor 4 Gen2
- Not suitable
- Synology DiskStation DS425+
- Better fit
In practice
Differences you will notice
Neither chassis is favored by the same hard-drive array
On either model, RAID 5 over four compatible 12 TB hard drives gives 36 TB before overhead. In this equal-drive example, picking ASUSTOR creates no extra hard-drive capacity and picking Synology takes none away.
How we worked this out
(4 - 1) × 12 TB = 36 TB before formatting and system overhead. Four SATA bays and RAID 5 support are common to both models.
Four positions are needed for two separate mirrored NVMe pairs
Four NVMe slots are needed for a plan with one two-SSD mirror for applications and another two-SSD mirror for a separate workload. The physical positions are there on AS5404T. DS425+ has just two, so it cannot build that exact all-NVMe layout internally.
How we worked this out
2 drives for the first mirror + 2 for the second = 4 NVMe positions. AS5404T has 4 and DS425+ has 2. Checks on software and compatible drives are still needed.
A narrow-shelf decision shifts with the shape of the cabinet
Compared with DS425+, AS5404T is 25 mm narrower but 7 mm deeper. ASUSTOR may suit a tight side-by-side shelf, and Synology may suit a shallow cabinet. Neither dimension comparison counts cable and ventilation clearance.
How we worked this out
199 - 174 = 25 mm of width difference. 230 - 223 = 7 mm of depth difference.
Option A
ASUSTOR, AS5404T
ASUSTOR Nimbustor 4 Gen2
A 4-bay chassis whose fastest documented network path is 2.5 Gbps.
- Best for
- Run four hard drives and several NVMe devices together
Facts we checked
- Positions for SATA drives: 4
- NVMe slots in M.2: 4
- Installed / maximum memory: 4 GB / 16 GB
- Ports for Ethernet: Two 2.5GbE
Option B
Synology, DS425+
Synology DiskStation DS425+
A 4-bay chassis whose fastest documented network path is 2.5 Gbps.
- Best for
- Run photos, shared files and backups through DSM
Facts we checked
- Positions for SATA drives: 4
- NVMe slots in M.2: 2
- Installed / maximum memory: 2 GB / 6 GB
- Ethernet ports: One 2.5GbE and one 1GbE
Spec by spec
Where they really differ
| Spec | ASUSTOR Nimbustor 4 Gen2 | Synology DiskStation DS425+ | In practice |
|---|---|---|---|
| SATA drive positions | 4 | 4 | Nominal capacity works out the same for the same equal-drive RAID layout. |
| M.2 NVMe slots | 4 | 2 | Two more physical NVMe positions are on ASUSTOR. |
| Installed / maximum memory | 4 GB / 16 GB | 2 GB / 6 GB | Look at what the actual apps require instead of only the maximum number. |
| Ethernet ports | Two 2.5GbE | One 2.5GbE and one 1GbE | A single 2.5GbE link is supported by each. More links take a suitable network configuration. |
| NVMe storage planning | Compatible NVMe storage or caching | Storage pools require Synology-verified SSDs | A physical slot does not mean any SSD you already own is supported. |
| Case width and depth | 174 × 230 mm | 199 × 223 mm | Synology is slightly shallower, and ASUSTOR is narrower. |
Trade-offs
What each pick costs you
With ASUSTOR Nimbustor 4 Gen2
- The diskless enclosure price goes up with NVMe and RAM upgrades.
With Synology DiskStation DS425+
- Synology-verified SSDs are required for M.2 storage pools.
Change of plan
When the answer changes
My plan calls for four internal NVMe devices
Go with ASUSTOR Nimbustor 4 Gen2. Four M.2 slots are found only on AS5404T.
I want DSM as my software environment
Go with Synology DiskStation DS425+. Four SATA bays come with the Synology workflow on DS425+.
Decision guide
How to decide
Pick the software before you fill the extra slots
The same basic storage layouts fit the four hard-drive bays on both models. ASUSTOR's extra NVMe slots and memory support count when a specific workload needs them. If what you mainly want is DSM's photo organization and backup routine, hardware capacity left unused elsewhere may matter less than that daily workflow.
Budget for the SSDs the platform really supports
Synology's current specifications allow M.2 storage pools, provided the SSDs are Synology-verified. Calling those slots cache-only would be wrong, and so would assuming any spare NVMe drive is supported. Check the exact drive and firmware before you build the budget around an SSD already in a drawer.
One transfer does not automatically use two Ethernet ports together
ASUSTOR has two 2.5GbE ports, whereas Synology pairs 2.5GbE with 1GbE. Either can serve a suitable client over one 2.5GbE path. Making good use of multiple links depends on the protocol, client and network setup. Adding the port labels together does not give a guaranteed copy speed.
What this page can’t tell you
- Storage figures assume compatible drives of equal capacity and decimal TB, counted before formatting, system space and metadata. RAID covers the drive failures it is specified for, but it does not replace a separate backup.
- Treat network figures as link rates. They are not measured file-transfer speeds. For the exact model you buy, check software support, memory revision, drive compatibility and the rest of the network.
By the numbers
What the data shows
What we found across the NAS devices we compare, plus the checked facts behind each finding.
Show the facts and the math
| Product | Needs it meets | Facts we checked | Sources |
|---|---|---|---|
| ASUSTOR Nimbustor 4 Gen2 |
|
| |
| Synology DiskStation DS425+ |
|
|
Ready to buy
See today’s price and what owners say
Open either model on Amazon for the current price, customer reviews and delivery options.
ASUSTOR Nimbustor 4 Gen2
Run four hard drives and several NVMe devices together
See price & reviews on AmazonSynology DiskStation DS425+
Run photos, shared files and backups through DSM
See price & reviews on AmazonEach link opens in a new tab.
We may earn a commission from qualifying Amazon purchases. How we make money