Synology DS720+ Review in 2026: Keep It, Upgrade It, or Buy Used?

Discontinued hardware still has a software runway

The Product Support Status picture is clear: DS720+ is Discontinued, DSM updates are Full, and Technical Support is Limited. That gives a home owner room to keep using a healthy box while treating support and hardware recovery more cautiously. It also means a business buyer should not confuse “still updated” with the same assistance level offered by a current fully supported system.

The J4125 is more interesting than the two-bay label

Intel Celeron J4125 gives DS720+ four cores and integrated graphics, while 2 GB of memory can be expanded officially to 6 GB. The CPU makes this tiny chassis capable of more than simple file serving, particularly for supported media conversion. The memory ceiling is the counterweight. A compact NAS can run applications, but application growth should not be allowed to crowd out its storage duties.

DSM 7.4 keeps it inside the modern management line

DS720+ remains eligible for the DSM 7.4 generation covered here. Owners should approach the update with the same discipline used on larger systems: verify backup recovery, document packages and read the exact release notes. Because DSM 7.4 cannot normally be downgraded, any specialized package or unsupported tweak deserves testing before the production box is changed.

Dual 1GbE looks older than the processor does

The two Ethernet ports are useful for failover and concurrent clients, but they do not provide native 2.5GbE to one workstation. A fast RAID set or SSD-backed workload can therefore sit behind a gigabit bottleneck. If the NAS mainly receives incremental backups overnight, that may not matter. If it feeds a 2.5GbE editing workstation, the network can become the decisive reason to move.

Small media servers are a natural fit

DS720+ pairs Intel graphics with a compact enclosure, so it remains attractive for a modest Plex or Jellyfin library where transcoding occurs. If the library itself is expanding rapidly, capacity architecture becomes the next question. Two internal bays can feel tight, but the DX517 option creates a path that most two-bay models lack. Evaluate playback needs and drive growth together.

Memory limits define the container ceiling

A few services can coexist comfortably with DSM, but 6 GB maximum memory is not a generous modern homelab budget. Watch swap use and service restarts before adding more. If the NAS is otherwise ideal, moving compute to a mini PC can preserve the Intel storage appliance. If both compute and network are becoming inadequate, replacing the platform can simplify more than one problem at once.

Two M.2 slots give the chassis a performance lever

NVMe sockets let the DS720+ use flash without sacrificing either main hard-drive bay, subject to current Synology support rules. Cache can help suitable small-file workloads, yet it cannot overcome gigabit networking or limited RAM. An SSD purchase is most rational after measuring the source of latency. Otherwise it becomes an expensive attempt to modernize the wrong layer.

The M.2 sockets also make DS720+ a useful example of why component upgrades should be workload-led. A cache that produces few hits consumes money and adds another component to monitor. A cache serving hot metadata or repeated small files can be worthwhile. DSM metrics and application behavior should decide which case you have, not the presence of empty slots.

DX517 is the reason this model deserves special treatment

One DX517 can lift DS720+ from two internal bays to seven total. Owners who already have the expansion unit can keep a compact head unit while gaining substantial storage. Buyers starting from zero should be more skeptical: used expansion pricing, cable availability and an older support lifecycle may make a current larger chassis the better system-level purchase.

Expansion and redundancy should be planned together

Adding bays changes more than capacity. It changes the RAID/SHR layout, rebuild exposure, future replacement count and backup size. Do not buy DX517 solely because it creates five extra slots. Model the actual drive arrangement and decide whether you want a long-lived seven-bay topology or are merely postponing a migration you will perform soon anyway.

Lifecycle preparation matters with a limited-support unit

Keep spare planning practical: know where the configuration backup is, maintain a data copy outside the NAS, and record which services must be recreated first. The goal is not to stockpile every component; it is to prevent the DS720+ enclosure from becoming a single point of organizational memory. That preparation also makes a future move to another Synology much less stressful.

Expansion cables and DX517 availability deserve the same attention as disks. An older expandable NAS is only as useful as the parts needed to maintain its topology. If replacement expansion hardware becomes scarce or expensive, a planned move to a current multi-bay chassis can be safer than waiting until a failure turns a convenient seven-bay design into a recovery exercise.

Used DS720+ is a specialist purchase

A used buyer should be specifically seeking Intel media capability, M.2 and expandable two-bay form factor. Otherwise newer two-bay models are easier to justify. Verify that the eSATA expansion connector, both network ports, M.2 sockets and fan behave correctly. A cheap chassis with a damaged expansion port loses much of what differentiates this model from simpler two-bay units.

DS725+ changes the value equation

DS725+ brings native 2.5GbE, far more memory headroom and the newer DX525 expansion generation. DS720+ counters with Intel media capability and compatibility with DX517. An existing owner may rationally stay; a new buyer usually needs a substantial discount to choose the older platform. The “better” NAS depends on which of those ecosystem traits you actually use.