Buying Guide
UNAS 2 vs DS225+ vs TS-264 vs AS5402T: Choose a Two-Bay NAS
Four brands, four useful directions: focused UniFi file storage, Synology DSM, QNAP expansion and ASUSTOR’s hybrid two-bay/four-M.2 design.
Choose UNAS 2 for focused UniFi file storage, DS225+ for the DSM workflow, TS-264 for QNAP’s connection and expansion options, or AS5402T when its four NVMe positions solve a real need. All four can belong on a two-bay shortlist, but their applications, memory and SSD routes differ. Start with the work you will actually do.
The familiar question is “Which NAS is best?” A better one is “What will I need it to do on an ordinary busy evening?” Phone uploads, backups, shared documents, media playback and containers place different demands on a small box. These models include newer and established current-catalogue choices; the newest name does not automatically win.
The Four Choices at a Glance
Compact UniFi Drive storage with 2.5GbE and specified PoE++ power. Focus on supported files, sharing and backup functions.
Two-bay DSM platform with a built-in 2.5GbE connection alongside Gigabit Ethernet.
Intel-based QTS platform with dual 2.5GbE, M.2 slots, HDMI and a supported PCIe upgrade route.
Two SATA bays plus four M.2 NVMe positions, dual 2.5GbE and ADM applications.
| Platform | Built-in Ethernet | SSD / expansion question |
|---|---|---|
| UNAS 2 | 1 × 2.5GbE | Two 3.5-inch HDD bays; no internal M.2 slots |
| DS225+ | 1 × 2.5GbE + 1 × Gigabit | Two SATA bays; no internal M.2 or PCIe card slot |
| TS-264 | 2 × 2.5GbE | Two M.2 NVMe positions and one PCIe slot; verify exact SKU |
| AS5402T | 2 × 2.5GbE | Four M.2 NVMe positions alongside two SATA bays |
The number of ports or slots does not predict an application benchmark. Check supported protocols, the supplied memory configuration, available PCIe bandwidth and the complete client path.
A File Store and an App Platform Are Different Briefs
Choose the Job Before the Enclosure
A focused file store and an application host have different requirements.
01 Files, photos and backup
A clear storage routineCheck the actual photo, sharing and restore workflow.
02 Applications and SSD workloads
A supported platform configurationAn x86 CPU or an M.2 socket does not prove every application or storage role is supported.
UNAS 2 is appealing when the task is straightforward shared files, user permissions, snapshots and supported backups within UniFi Drive. Its ARM platform and focused software are not a promise of Docker, virtual machines or Protect camera recording. If the brief is a file store, simplicity can be a benefit rather than a missing feature.
DS225+ is a compact route into DSM’s supported file, photo and backup applications. Check package compatibility and required resource limits. Its Intel J4125 processor name alone does not establish that a particular current media application exposes hardware transcoding; software support is a separate check.
TS-264 provides an Intel x86 QTS platform and more connection options. That can suit a mixed home-lab or creator workload, but verify the application, licence, memory revision and supported add-in card before assuming that every possible upgrade is available at once.
AS5402T combines an Intel x86 platform with four M.2 positions. This is particularly interesting when a supported SSD workload belongs alongside HDD capacity. It is not a reason to buy four SSDs immediately: choose the intended storage/cache role, thermal arrangement and independent backup first.
When 2.5GbE Is Enough, and When It Is Not
A single 2.5GbE link has a raw line rate of 312.5 MB/s before protocol overhead. That is a connection limit, not a file-copy promise. Many small files, a busy disk pool, WiFi conditions or a Gigabit client can keep the result below it.
Dual ports can help supported multi-client, failover or multichannel designs, but do not automatically double every copy. A computer needs the right adapter and protocol support, and the switch must be part of the plan.
If repeated large transfers justify faster networking, cost the supported path on the exact NAS. An add-in card can make a platform more flexible, while a fixed-network design may be enough for years if the workload stays modest. Use transfer troubleshooting before paying to fix an unmeasured bottleneck.
Power, Mirroring and the Next Capacity Upgrade
UNAS 2’s specified power method is PoE++, with an included compatible adapter. A normal PoE or PoE+ port is not automatically sufficient. Confirm the switch or injector’s standard, power budget and intended data rate. Back up the device and its supplying network path appropriately.
For a conventional two-drive mirror, two equal 12 TB drives leave about 12 TB of nominal protected capacity before formatting and system use. The second drive provides redundancy, not twice the protected space. UNAS 2 currently specifies RAID 1; other supported platforms can offer additional layouts with different consequences.
Capacity expansion later may involve replacing both drives sequentially or migrating to a different system. Do not assume external USB capacity extends the same internal RAID pool. Keep a verified backup before replacement and allow enough time for repair between supported steps.
Model the starting layout with the RAID capacity calculator. Budget the recovery copy as part of the purchase, rather than using the entire budget on the primary enclosure.
A Clear Recommendation by Use
For a focused UniFi file store, shortlist UNAS 2. For a familiar DSM file and photo workflow, shortlist DS225+. For supported QNAP applications and hardware expansion, examine TS-264. For a deliberate HDD-plus-NVMe design, include AS5402T. Choose only after checking the applications, capacity after mirroring and the complete backup path.
Frequently Asked Questions
Can all four run the same apps?
No. UniFi Drive, DSM, QTS and ADM expose different applications and support limits. Match the exact required application before comparing processor names.
Does UNAS 2 need a separate router?
It provides storage, not internet routing. It needs a suitable existing network and the specified PoE++ power arrangement.
Do four M.2 slots make AS5402T a six-drive HDD NAS?
No. It has two SATA bays and four M.2 NVMe positions. These are different connections with model-specific supported storage roles.
Are all TS-264 memory configurations identical?
No. Check the full SKU and hardware revision before ordering memory or describing the supplied configuration.
Is RAID 1 sufficient protection for family photos?
It helps with certain drive failures but not every deletion, ransomware incident or loss of the whole unit. Keep an independent versioned backup and test a restore.
Should I start with two bays or four?
Estimate protected capacity, growth, failure tolerance and the cost of later migration. Four bays provide more layout choices, while a two-bay system can be sufficient for a defined smaller workload.
