Synology DS425+ vs DS925+

Choose the Synology DS925+ for ECC memory, a larger supported memory ceiling and documented drive expansion; choose the DS425+ when four SATA bays and a single multi-gig connection cover your file-and-backup needs. For Plex or Jellyfin video transcoding, buy neither on CPU branding alone: the DS425+'s Intel graphics do not establish Plex support, while the DS925+'s processor has no integrated GPU.

Official specifications and application documentation checked November 2, 2026.

Quick picks by workload

Compare specifications and all conditions

File sharing, backups and compatible media playback; staying within four disks

Our pick

DS425+

What decides it

One 2.5GbE connection; no requirement for ECC or an expansion chassis

Several services, a larger memory requirement, or a documented expansion plan

Our pick

DS925+

What decides it

ECC, up to 32 GB RAM and DX525 support

A second multi-gig NAS connection

Our pick

DS925+

What decides it

Two 2.5GbE ports, versus one 2.5GbE plus one gigabit on DS425+

Video conversion is essential

Our pick

Separate supported media host

What decides it

Check the software support and your files before choosing either NAS as storage

Full comparison table ↔

Swipe to compare. Row labels stay visible.

Your actual job	Our pick	What decides it
File sharing, backups and compatible media playback; staying within four disks	DS425+	One 2.5GbE connection; no requirement for ECC or an expansion chassis
Several services, a larger memory requirement, or a documented expansion plan	DS925+	ECC, up to 32 GB RAM and DX525 support
A second multi-gig NAS connection	DS925+	Two 2.5GbE ports, versus one 2.5GbE plus one gigabit on DS425+
Video conversion is essential	Separate supported media host	Check the software support and your files before choosing either NAS as storage

Your actual job	Our pick	What decides it
File sharing, backups and compatible media playback; staying within four disks	DS425+	One 2.5GbE connection; no requirement for ECC or an expansion chassis
Several services, a larger memory requirement, or a documented expansion plan	DS925+	ECC, up to 32 GB RAM and DX525 support
A second multi-gig NAS connection	DS925+	Two 2.5GbE ports, versus one 2.5GbE plus one gigabit on DS425+
Video conversion is essential	Separate supported media host	Check the software support and your files before choosing either NAS as storage

Compare ecosystems in Synology vs UGREEN, or enclosure sizes in best NAS for home.

Compare the exact configurations

These are the DS425+ and ECC-equipped DS925+, using Synology's comparison, Intel's J4125 specifications and AMD's V1000 brief.

The similarly named DS925neo+ ships with 4 GB non-ECC memory. Synology's shared product page places its column beside the DS925+; check the full model name rather than assuming that matching RAM capacity means ECC.

Both processors have four cores. Plan memory against the published limits; these are not application benchmarks:

• DS425+6GB
• DS925+32GB

Source: Synology hardware comparison

DS425+: best for a fixed four-bay build

Choose this for a file-and-backup system when its documented configuration meets your requirements: four SATA bays, a 2.5GbE port and memory expandable to 6 GB. Choose the DS925+ if your application plan exceeds that memory ceiling or needs expansion.

Photos changes the parts list. Synology says object recognition in Synology Photos requires at least 4 GB memory; the DS425+ ships with 2 GB. Its supported D4NS01-4G expansion module adds 4 GB for a 6 GB configuration. Include that officially listed module when object recognition is required, rather than comparing the stock boxes as complete photo-server builds.

The Intel graphics are a hardware distinction, but read the playback caveat below before making them your purchase reason.

DS925+: best for ECC and future expansion

The DS925+ is our choice when you need ECC, more than 6 GB RAM, another 2.5GbE connection or the DX525. ECC means memory with error correction. Its 4 GB factory configuration meets the Photos object-recognition memory threshold; size RAM for your combined workload.

Plan the final memory configuration before ordering. Synology documents a maximum of 32 GB as two 16 GB modules, and says multiple modules must be identical and share a model number. Reaching that maximum means replacing the factory module. Do not count the original 4 GB on top of the maximum.

For a media library, choose it as storage beside separate compute when conversion is required. AMD's exact V1500B row has no integrated GPU; adding RAM does not change that processor specification.

Check your screens before buying for Plex or Jellyfin

Plex's playback guide distinguishes Direct Play, which sends a compatible file unchanged, from Direct Stream, which repackages streams with little processing. Incompatible subtitles can force a full video transcode even when the video itself is compatible.

Record every screen's device, app, codecs, container, subtitles and local/remote quality setting. Try representative files with subtitles enabled; record the playback result. Use our Jellyfin vs Plex hardware worksheet for the detailed decision.

• Yes: Direct Play: choose the NAS by storage, memory and networking requirements
• Partly: Direct Stream or audio-only conversion: distinguish this from full video conversion
• No: Required video transcode: validate a supported acceleration path before buying

The DS425+ trap: Plex's own NAS sheet currently marks its hardware-transcoding columns No, with a dated investigation note, despite Intel listing Quick Sync. Treat this as unresolved application support. Plex also requires an active Plex Pass for hardware acceleration; a subscription alone does not resolve compatibility.

Jellyfin's hardware guidance advises against buying the older Intel J-series class and warns about prebuilt NAS software environments. Our recommendation for essential transcoding is a separate host chosen from the application's supported hardware guidance, with either NAS providing storage. Do not assume a simultaneous-stream count from the CPU name.

Trace the entire file-transfer path

Start with NAS port → cable → switch port → any intervening uplink → computer adapter. Check each negotiated link; a gigabit segment limits traffic crossing it, even if both end devices advertise multi-gig. This follows the port limits in NETGEAR's multi-gig explanation.

For a straightforward setup, connect either NAS's 2.5GbE port and a 2.5GbE-capable computer to suitable ports on the same multi-gig switch. This is a link-rate plan, not promised disk throughput. Check the LAN path before upgrading your internet plan to address local file transfers.

The DS925+'s extra port is useful only with a plan for it. Synology distinguishes SMB3 Multichannel from Link Aggregation: the former can improve a single SMB client's throughput with a qualifying configuration; the latter does not improve single-client throughput. Verify DSM, SMB service, client OS and adapter requirements. Simply plugging in both NAS ports does not double a file copy.

Choose drives, usable capacity and a separate backup

The drive example is the WD Red Plus 8 TB WD80EFPX, a CMR SATA disk with 256 MB cache, 5640 RPM and an up-to-215 MB/s transfer specification, according to WD's exact-model table. Match that model; family-wide maximum speeds are not its specification.

Drive policy matters more than the brand badge. Synology's DSM 7.3 announcement allows third-party drives for installation and pool creation on 2025 DiskStation Plus models. It does not certify every disk/firmware combination. Check the NAS compatibility list; M.2 pools and cache still require HCL-listed drives. The WD example is not a claim of Synology certification. See best NAS hard drives for selecting capacity and drive class.

Calculated examples using equal 8 TB disks and Synology's RAID formulas:

These are decimal capacity calculations, not formatted free-space promises. Allow for system/filesystem overhead, growth and backup history. SHR is another supported choice; Synology documents single-drive fault tolerance for SHR-1 when enough disks are installed.

Choose a separate destination before filling the NAS. Hyper Backup supports external devices, another Synology, rsync and cloud destinations, with scheduling and version retention. Size the destination for the data you will protect and the versions you retain. Our recommendation is an external backup plus an off-site copy of irreplaceable data; verify a restore before depending on either.

Expansion means the DX525, not any USB-C box

The DX525 adds five SATA bays to a supported DS925+, making nine total. Its package includes the USB Type-C expansion cable, power adapter and power cord. Use that documented connection; the connector shape does not establish compatibility with another enclosure. The DS425+ has no documented DX525 path.

Synology supports volumes spanning the host and expansion unit, but recommends keeping a volume physically within one unit for better performance. Follow that recommendation when planning a new build. The DX525 page also says compatible drives are mandatory: recheck its own drive policy rather than assuming the host's third-party-drive permission covers expansion.

A DX525 volume used for primary storage is not the separate backup in our parts lists. Keep that backup destination even after adding expansion capacity.

Buy a complete configuration

These examples assume you want the four-disk RAID 5 configuration above. Recalculate storage and backup requirements if starting smaller. Buy the named diskless enclosure; if considering a drive bundle, verify the disk models, quantities and RAM configuration separately.

C2 Storage for Hyper Backup requires an eligible subscription. Include that commitment if choosing C2 as the off-site destination. For essential video conversion, add the separate media host to either configuration before comparing what you need to buy.

Commission the storage, backup and playback plan in that order:

1. 1

   Confirm the configuration

   Check exact enclosure, memory variant, drive models and compatibility policy.

2. 2

   Set up recovery

   Configure the separate backup, retained versions and off-site destination; verify a restore.

3. 3

   Check the workload

   Confirm negotiated links and playback results using the files and subtitles you need.

How we choose

We compare official Synology specifications, accessory compatibility and drive policy with Intel and AMD processor documentation and the applications' own support guidance. Our picks favor a configuration that meets a named workload; clock speeds and advertised port rates are not benchmark results. These recommendations are document-based, without physical testing. Synology's current status page lists full DSM-update and technical support for both models; recheck that status before buying. Full method: How we choose.

Verdict

Get the DS425+ for a fixed four-bay file-and-backup build, adding supported RAM when Photos object recognition is required. Get the DS925+ when ECC, its larger memory ceiling, another multi-gig connection or DX525 expansion has a defined job. Resolve media playback first, and keep the separate backup in either build.