NAS
QNAP TS-673A vs Synology DS1621+: Six Bays, ECC and Network Upgrades
The same Ryzen processor does not make these six-bay NAS systems interchangeable. Compare memory protection, software and the network upgrade path.
Choose the TS-673A for its built-in 2.5GbE and flexible QNAP expansion; choose the DS1621+ when DSM, supplied ECC memory and the Synology workflow fit. They share an AMD Ryzen V1500B processor class, but differ in memory configuration, ports and software choices. Size the whole system for the workload.
Six bays can be a useful middle ground for a studio or business: more drive-layout choices than a two-bay NAS, without moving straight to a large rack. The mistake is to assume that a shared processor predicts identical file-copy speed, app support or recovery behaviour.
The Six-Bay Differences at a Glance
Six bays, dual 2.5GbE, two M.2 slots and two PCIe slots. Choose supported QTS or QuTS hero deployment deliberately.
Six bays, supplied ECC memory and four Gigabit ports, with a supported PCIe path for faster networking.
| Feature | TS-673A | DS1621+ |
|---|---|---|
| Processor | AMD Ryzen V1500B, 4 cores / 8 threads, 2.2 GHz | AMD Ryzen V1500B, 4 cores / 8 threads, 2.2 GHz |
| Supplied memory | 8 GB DDR4; compatible ECC configuration supported | 4 GB DDR4 ECC |
| Official memory ceiling | 64 GB | 32 GB |
| Built-in Ethernet | 2 × 2.5GbE | 4 × 1GbE |
| PCIe | 2 × Gen 3 ×4 slots | 1 × Gen 3 ×8 slot with a ×4 link |
| M.2 | 2 × NVMe, Gen 3 ×1 each | 2 × NVMe slots; check supported cache/pool roles |
| Operating-system choice | QTS or supported QuTS hero | DSM |
Neither platform includes a general-purpose integrated GPU. QNAP supports selected graphics-card configurations, but physical fit, power, drivers and application support matter. Do not assume that a PCIe socket makes every GPU or transcoding workload supported.
ECC and the File System Solve Different Problems
Protect Different Failure Paths
ECC, storage checks and backup are complementary.
01 Within the working system
Protection inside the NASThe installed configuration and file-system support matter.
02 Beyond the working system
A usable recovery routeRedundant drives do not replace a separate copy or prove a restore.
ECC memory can detect and correct supported memory errors. The DS1621+ ships with ECC; on the TS-673A, verify the actual supplied modules and compatible ECC upgrade configuration. “ECC supported” does not mean every unit is already using ECC.
QTS and QuTS hero are alternative installations with different file-system and storage behaviour. QuTS hero uses ZFS; DSM offers supported Btrfs functions on this platform. Checksums, snapshots, redundancy and backup each address different failure modes, and none makes the system immune to operator error or ransomware.
Choose the operating system before commissioning the storage pool. Do not switch a populated system between QTS and QuTS hero expecting the existing pool to follow without a documented migration. Plan a full backup and supported restoration path.
Upgrade the Path, Not Just the NAS
The TS-673A starts with 2.5GbE ports. The DS1621+ starts with Gigabit interfaces and can use a supported add-in card for faster connectivity. Include the client adapter, switch ports and suitable cable or transceiver in that upgrade; a 10GbE card alone is not a 10GbE workflow.
Four network ports do not mean four times the speed for every file copy. Protocol support, client connections and switch configuration govern whether parallel links help. The slow-transfer guide explains how to isolate the actual limit.
Use M.2 SSDs only for supported tasks. A read cache, a protected write cache and a direct SSD storage pool are different designs. Compare endurance and power-loss behaviour for the intended workload, not just the SSD’s maximum sequential read figure.
Six Bays Need a Recovery Plan
Six equal 16 TB drives provide 96 TB raw. A conventional RAID 6 design leaves about 64 TB before formatting and system overhead; RAID 5 leaves about 80 TB with less drive-failure tolerance. These calculations do not include snapshots, reserved space or a backup copy.
Use the RAID capacity calculator to explore layouts, then verify current drive and expansion compatibility. The DS1621+ supports up to 16 drive positions with two optional DX517 expansion units. An expansion-unit count is not a promise of one enormous supported pool. Keep restore speed and future rebuild time in the brief, especially when capacity grows.
For a new project, cost the enclosure, appropriate memory, network path, supported drives and an independent backup together. For an existing owner, upgrade only the measured bottleneck and preserve the working recovery copy before changing the storage layout.
Frequently Asked Questions
Does the same Ryzen CPU mean the same NAS performance?
No. Memory, network links, disks, file system, encryption, applications and concurrent work all influence the result. Test the intended workload.
Does the TS-673A include ECC memory?
The platform supports compatible ECC memory, but support is different from the installed configuration. Check the exact unit and ordered modules.
Can I move a QTS pool straight into QuTS hero?
Do not assume so. They use different storage architectures. Follow the documented migration procedure with a complete verified backup.
Does the DS1621+ have 10GbE as standard?
Its built-in interfaces are four Gigabit ports. Faster networking requires a compatible add-in option and a suitable client and switch path.
Do more bays remove the need for backup?
No. Redundancy supports availability through certain drive failures. Keep a versioned copy independent of the working NAS and test recovery.
Should I use all six bays immediately?
Choose a supported layout from capacity, failure tolerance and growth needs. Leave operating headroom and plan the cost and duration of later expansion, rather than filling every bay without a recovery design.
