Synology DS425+ vs DS925+: Media Server or Backup NAS?

Quick Summary (TL;DR):
The Synology DS425+ and DS925+ share four SATA bays, two M.2 NVMe slots, DSM, Btrfs, SHR, Hyper Backup, Snapshot Replication, Synology Photos and Container Manager, but they target different workloads. The DS425+ uses an Intel Celeron J4125 with four cores/four threads, 2GB non-ECC DDR4 expandable to 6GB, one 2.5GbE plus one 1GbE port, and Intel Quick Sync Video. That makes it the more interesting of the two for light Plex/Jellyfin transcoding, although the J4125 is an older processor and Plex currently recommends Jasper Lake or newer for reliable HEVC-output transcoding on NAS. The DS925+ uses a Ryzen V1500B with four cores/eight threads, 4GB ECC DDR4 expandable to 32GB, dual 2.5GbE and support for the DX525 expansion unit, taking it from four to nine bays. It is the stronger choice for backups, larger Docker/VM workloads, ECC memory, multiple users and long-term storage growth. If most media Direct Plays, choose based on storage and software needs rather than transcoding. If hardware transcoding is central, the DS425+ has the better architecture of these two, but a newer Intel NAS may be a better dedicated media-server purchase.

Synology DS425+ vs DS925+ at a Glance

Feature	DS425+	DS925+
CPU	Intel Celeron J4125	AMD Ryzen V1500B
Cores / threads	4 / 4	4 / 8
CPU frequency	2.0GHz base / 2.7GHz burst	2.2GHz
Integrated video	Intel UHD Graphics / Quick Sync	No Intel Quick Sync
Included RAM	2GB DDR4 non-ECC	4GB DDR4 ECC
Maximum RAM	6GB	32GB
SATA bays	4	4
M.2 NVMe slots	2	2
Networking	1 × 2.5GbE + 1 × 1GbE	2 × 2.5GbE
Expansion unit	No dedicated bay expansion	DX525; up to 9 total bays
Maximum single volume	108TB	108TB or up to 200TB with 32GB RAM where supported
Virtual Machine Manager	Supported	Supported
Best fit	Compact media + family NAS	Backup, Docker/VMs, storage growth

The Models Look Similar Until You Examine the Workload

Both are four-bay Synology Plus systems running the same DSM ecosystem. Both can store family files, back up computers, run Synology Photos, host containers and serve media.

The real difference is where the hardware budget went:

DS425+
Intel iGPU / Quick Sync
lower RAM ceiling
no bay expansion

DS925+
more CPU threads
ECC memory
32GB RAM ceiling
dual 2.5GbE
DX525 expansion

That is why “which one is faster?” is the wrong question. The better model depends on whether your NAS is primarily a media appliance or a storage/backup server.

DS425+: Intel J4125 Is the Media Advantage

The DS425+ uses Intel’s Celeron J4125:

• 4 cores.
• 4 threads.
• 2.0GHz base frequency.
• Up to 2.7GHz burst.
• Intel UHD Graphics 600.
• 12 graphics execution units.
• Intel Quick Sync Video.

Quick Sync matters because Plex and other media servers can use supported Intel video hardware for decoding and encoding rather than doing every transcode on the CPU.

That gives the DS425+ an architectural advantage for media over the DS925+’s Ryzen V1500B, which does not provide Intel Quick Sync.

But the J4125 Is Not a Modern Transcoding Powerhouse

The media advantage needs an important qualification.

The J4125 is an older Gemini Lake Refresh processor. Plex’s current hardware-accelerated streaming documentation says NAS users need Jasper Lake or better to reliably transcode to HEVC output.

So the DS425+ is best described as:

• Very good for Direct Play.
• Useful for supported hardware-assisted H.264/legacy media workflows.
• Capable of some hardware transcoding where Plex and the codec path support it.
• Not the NAS to buy specifically for demanding modern multi-stream HEVC transcoding.

Plex also requires an active Plex Pass for normal hardware-accelerated streaming.

DS925+: Ryzen V1500B Is the Server Advantage

The DS925+ uses AMD’s Ryzen V1500B:

• 4 cores.
• 8 threads.
• 2.2GHz.
• 64-bit x86 architecture.
• Hardware encryption engine.

The eight CPU threads and much larger memory ceiling make the DS925+ more comfortable when the NAS is running several services simultaneously.

SMB/NFS
+ backups
+ Synology Photos
+ Docker
+ databases
+ Virtual Machine Manager
+ surveillance
= DS925+ workload territory

For pure media transcoding, however, more general CPU threads do not replace a supported hardware video engine.

Direct Play Changes the Entire Plex Decision

If your TVs, phones and streaming boxes can play the original video and audio formats, Plex may use Direct Play instead of transcoding.

Direct Play requires very little CPU. In that situation:

• The DS425+’s Quick Sync advantage matters much less.
• The DS925+’s storage and RAM advantages become more important.
• Network bandwidth and drive capacity matter more than video acceleration.

If nearly everything Direct Plays, choose the better NAS, not the better transcoder.

For a broader current media shortlist, see Best NAS for Plex and Jellyfin Hardware Transcoding.

RAM Is the Biggest General-Purpose Difference

The DS425+ ships with 2GB DDR4 non-ECC memory and has one expansion slot. Synology lists the maximum as 6GB total.

The DS925+ ships with 4GB ECC DDR4 and has two memory slots, supporting up to 32GB.

Workload	DS425+	DS925+
File serving	Comfortable	Comfortable
Synology Photos	Suitable; more memory helps indexing/features	More headroom
Several containers	6GB ceiling can become limiting	Up to 32GB gives much more flexibility
Virtual machines	Supported but RAM is restrictive	Much better fit
Large multi-service NAS	Limited	Better fit

ECC Memory Is Another DS925+ Advantage

The DS925+ uses ECC memory; the DS425+ does not.

ECC can detect and correct certain memory errors before bad data is passed further through the system. It does not make a NAS immune to corruption, but it is a useful reliability feature in a machine whose main job is storing important data.

For family photos, business files or long-term backup repositories, that is a more meaningful advantage than a small CPU benchmark difference.

Networking: DS925+ Has Dual 2.5GbE

The DS425+ provides:

• 1 × 2.5GbE.
• 1 × 1GbE.

The DS925+ provides:

• 2 × 2.5GbE.

For one workstation, the practical maximum is normally determined by the link the client actually uses. Dual ports are most useful for redundancy, network separation or aggregate traffic across several clients.

Do not assume two 2.5GbE ports automatically give one ordinary SMB connection 5Gbps.

Both Have Four SATA Bays and Two M.2 Slots

Both models support:

• 4 × 3.5-inch SATA HDD or 2.5-inch SATA SSD.
• 2 × M.2 2280 NVMe SSD.
• SHR.
• Basic/JBOD.
• RAID 0/1/5/6/10.
• M.2 caching.
• M.2 storage pools where supported with verified SSDs.

That means the DS425+ does not sacrifice internal bay count or NVMe slot count compared with the DS925+.

The DS925+ Can Expand to Nine Bays

This is the biggest long-term storage difference.

The DS925+ supports one DX525 five-bay expansion unit, increasing total drive bays from four to nine.

The DS425+ does not have the corresponding expansion path.

If you expect four drives to remain enough for the life of the NAS, this does not matter. If you already suspect you may outgrow four bays, the DS925+ avoids an earlier enclosure replacement.

Maximum Volume Size Also Favours the DS925+

Synology currently lists the DS425+ at a maximum single volume size of 108TB.

The DS925+ supports 108TB volumes normally and can support up to 200TB for qualifying configurations with 32GB memory installed.

This is irrelevant to most home users today, but it reflects the DS925+’s role as the more scalable storage platform.

DSM Features Are Largely Shared

Because both are Plus-series DiskStations, many of the reasons people buy Synology apply to both.

• Btrfs.
• Synology Hybrid RAID.
• Hyper Backup.
• Snapshot Replication.
• Synology Drive.
• Synology Photos.
• Container Manager.
• Virtual Machine Manager.
• Surveillance Station.
• SMB/NFS/iSCSI services.

The question is not whether DS425+ has “real DSM” and DS925+ has “better DSM”. The difference is how much hardware each model gives those applications.

Virtual Machine Manager Works on Both—but RAM Changes the Usefulness

Synology currently lists both DS425+ and DS925+ as supported models for Virtual Machine Manager.

That does not make them equally suitable VM hosts.

With a 6GB maximum, the DS425+ quickly runs out of memory after DSM and normal NAS applications take their share.

The DS925+ can reach 32GB and has eight CPU threads, making it a much more credible platform for several containers or one or more useful VMs.

Docker / Container Manager: DS925+ Has More Growth Room

A small Docker stack can run on either model.

Pi-hole
+ MQTT
+ Vaultwarden
+ small web service

The DS425+’s 6GB maximum becomes restrictive when you add applications such as:

• Immich.
• PostgreSQL.
• Nextcloud.
• Several databases.
• Media servers.
• Multiple monitoring tools.

The DS925+’s 32GB ceiling makes it the more sensible Synology if the NAS will evolve into a serious self-hosting platform.

Synology Photos Works on Both

Both support Synology Photos, including facial-recognition functionality.

Synology notes that object recognition on the DS425+ requires upgrading the system to at least 4GB memory.

For a large photo library with several simultaneous applications, the DS925+’s extra memory and CPU threads give it a more comfortable long-term position.

Backup NAS: The DS425+ Is Already Very Capable

Do not assume the DS925+ is automatically required for backups.

The DS425+ already supports the DSM storage and backup features most households need:

• Btrfs.
• SHR and standard RAID.
• Hyper Backup.
• Snapshot Replication.
• Synology Drive.
• External USB backup.
• Remote/cloud backup destinations.

If four bays, 6GB RAM and one 2.5GbE connection are enough, the DS425+ can be an excellent backup NAS.

So Why Buy the DS925+ for Backups?

The DS925+ becomes worthwhile when the backup appliance is larger or more critical.

• ECC memory.
• More simultaneous backup jobs.
• More RAM for applications and caching.
• Dual 2.5GbE.
• Expansion to nine bays.
• Larger potential volumes.
• More headroom for Docker and VMs alongside backups.

It is less about making one laptop backup faster and more about supporting a larger storage environment for longer.

Current Drive Compatibility: DSM 7.3 Changed the 2025 Story

Both DS425+ and DS925+ are 2025 Plus-series models, so older launch reviews often describe a stricter drive policy than users see under current DSM.

With DSM 7.3, Synology allows non-listed third-party HDDs and 2.5-inch SATA SSDs to be used for new storage-pool creation on 2025 DiskStation Plus desktop models, provided the drives are not explicitly on the incompatibility list.

Synology still recommends verified drives and may limit support for faults caused by an unverified drive.

M.2 NVMe is stricter: new M.2 storage pools and cache require compatible/verified SSDs on these systems.

For the full buying implications, see NAS Drive Compatibility: What to Check on Synology, UGREEN and QNAP.

M.2 NVMe: Same Slot Count, Similar Policy

Both models include two M.2 NVMe slots and both can support M.2 storage pools in supported configurations.

Synology’s current policy requires verified M.2 drives for new storage-pool or cache creation on the affected 2025 DiskStation Plus systems.

Do not buy random consumer NVMe drives assuming they will behave like ordinary SATA disks in DSM.

Power Consumption: DS425+ Is the Lighter Platform

Synology publishes the following figures under its own test conditions:

• DS425+: 28.25W during access, 6.10W during HDD hibernation.
• DS925+: 37.91W during access, 12.33W during HDD hibernation.

These figures are model-specific Synology tests rather than universal wall-power guarantees. Drive model, RAM, SSDs, network traffic and application load all affect real consumption.

For a NAS that spends most of its life storing backups and occasionally streaming media, the lower-power DS425+ can be attractive.

Noise Is Practically a Draw

Synology lists:

• DS425+: 21.6dB(A).
• DS925+: 20.5dB(A).

Both use two 92mm fans and the same basic chassis dimensions of 166 × 199 × 223mm.

In practice, the installed hard drives will often be more audible than the one-decibel difference in Synology’s own test results.

Which One for Plex?

Plex workload	Better fit	Why
Mostly Direct Play	Either	Transcoding hardware matters little
Occasional supported hardware transcode	DS425+	Intel Quick Sync
Modern HEVC-output transcoding	Consider a newer Intel NAS	Plex recommends Jasper Lake or newer for reliable NAS HEVC output
Large library + no transcoding	DS925+	More RAM, dual 2.5GbE and expansion path

Which One for Family Backup?

For a normal household with four drives and moderate growth, the DS425+ already provides the important DSM backup features.

The DS925+ becomes more attractive if the same NAS must also:

• Run many containers.
• Host VMs.
• Serve several users simultaneously.
• Use ECC memory.
• Expand beyond four bays.
• Grow into a small-office storage server.

Which One for Docker and Home Lab Use?

The DS925+ is the much stronger choice.

The difference is not only CPU threads. The 32GB memory ceiling changes what can realistically coexist on the NAS.

If your home-lab plans are substantial enough that 32GB might eventually be useful, you should also compare Synology against more hardware-oriented NAS brands or a separate mini PC plus NAS architecture.

Our general four-bay comparison is here: Best 4-Bay NAS for Docker, Plex and Family Storage.

Complete-System Cost Matters More Than the Chassis Difference

Whichever model you choose, the complete build includes:

• NAS enclosure.
• Four HDDs.
• Memory upgrade if required.
• M.2 SSDs if justified.
• UPS.
• External or off-site backup storage.
• 2.5GbE switch/client adapter if you want faster networking.
• DX525 later if planning DS925+ expansion.

For many buyers, four large NAS drives will cost more than the difference between DS425+ and DS925+. Do not optimise the wrong line item.

A Practical Buying Matrix

Your priority	Better fit	Reason
Basic family backup	DS425+	Same core DSM backup ecosystem for less hardware
Mostly Direct Play media	Either	CPU transcoding matters little
Light Intel Quick Sync transcoding	DS425+	J4125 includes Quick Sync
Heavy modern transcoding	Neither is ideal	Look at newer Intel media hardware
Docker / many services	DS925+	32GB RAM ceiling and 8 threads
Virtual machines	DS925+	Much more RAM headroom
ECC memory	DS925+	ECC included
Expand beyond four HDDs	DS925+	DX525 expands to nine bays
Lowest power for four-bay DSM NAS	DS425+	Lower Synology-published power figures

Synology DS425+ vs DS925+: The Bottom Line

The DS425+ is the sensible choice when you want four-bay DSM storage without paying for server headroom you will not use. It is excellent for backups, family files, Synology Photos, Direct Play media and light container workloads. Its Intel J4125 also gives it Quick Sync, making it the more media-friendly architecture of these two for supported hardware transcoding.

The DS925+ is the stronger long-term storage and application platform. ECC memory, 32GB RAM support, eight CPU threads, dual 2.5GbE and DX525 expansion matter when the NAS is hosting more users, containers, VMs or substantially more storage.

For Plex specifically, do not make the mistake of reading “Intel Quick Sync” and assuming the DS425+ is a modern transcoding monster. Plex currently recommends Jasper Lake or newer for reliable HEVC-output transcoding on NAS, while the J4125 is an older generation.

The useful decision is therefore: DS425+ for a compact DSM backup/media appliance; DS925+ for ECC, applications and storage growth.

Continue the NAS Buying Series

• Best 4-Bay NAS for Docker, Plex and Family Storage
• Best NAS for Plex and Jellyfin Hardware Transcoding
• NAS Drive Compatibility: What to Check on Synology, UGREEN and QNAP

Datasheets & External Resources

• Synology – DS425+ vs DS925+ official comparison
• Synology DS425+ – Official specifications
• Synology DS925+ – Official specifications
• Intel Celeron J4125 – Quick Sync and graphics specifications
• Plex – Hardware-accelerated streaming requirements
• Plex – NAS compatibility and hardware-transcoding guidance
• Synology Virtual Machine Manager – Supported models
• Synology – DSM 7.3 drive compatibility policies