TerraMaster d4-320u

Key Specifications

General

• Device type: 4‑bay direct‑attached storage (DAS) enclosure

• Drive bays: 4 × SATA slots (3.5″ and 2.5″)

• Supported drive types:

  • 3.5″ SATA HDD

  • 2.5″ SATA HDD

  • 2.5″ SATA SSD

• File systems supported: NTFS, APFS, FAT32, EXT4, exFAT

Storage & Performance

• Maximum raw capacity: up to ~96 TB (24 TB × 4 drives)

• RAID support: Single disks only (no hardware RAID)

• USB interface: USB 3.2 Gen 2 Type‑C (10 Gbps)

• Max read speed: ~1016 MB/s (with 4 SSDs)

• Max write speed: ~960 MB/s (with 4 SSDs)

• HDD sleep support: Yes

Physical & Power

• Dimensions (HxWxD): ~45 × 440 × 241 mm

• Weight: ~2.7 kg (net) / ~4.5 kg (gross)

• System fans: 3 × 40×40×20 mm (smart control)

• Noise level: ~26.7 – 35 dB(A) (depending on spec version)

• Power supply: 72 W adapter (100–240 V AC input)

• Typical power consumption: ~45.5 W (active), ~8.1 W (hibernation)

Environment & Compatibility

• Operating temperature: 0 °C – 40 °C

• Storage temperature: ‑20 °C – 60 °C

• Relative humidity: 5 % – 95 % RH

• Supported OS: Windows, macOS, Linux

Included Accessories

• 1 × USB‑C to USB‑C cable (10 Gbps)

• 1 × USB‑A to USB‑C cable (10 Gbps)

• Power adapter & cable

• Screws and quick install guide

Features

1. Massive Multi‑Drive Storage Capacity

The D4‑320U supports up to four SATA drives — whether 3.5″ hard drives or 2.5″ SSDs — and offers a huge raw storage potential, often up to around 120 TB depending on which drives you install. That means you can store massive libraries of files, media, backups, or project data in one place instead of spreading them across many smaller devices — great for businesses, creatives, or anyone with heavy storage needs.

2. USB 3.2 Gen 2 High‑Speed Connectivity (10 Gbps)

The unit uses USB 3.2 Gen 2, which delivers up to 10 Gbps bandwidth — that’s about 10 times faster than older USB 2.0 ports. In real use with multiple drives installed, read/write speeds can reach up to ~1016 MB/s — fast enough for large file transfers, video editing, and rapid backups. This speed comes from the combination of the USB interface and the drives you install.

3. Plug‑and‑Play Compatibility

No drivers are needed — just connect the enclosure to a computer or compatible NAS with the included USB cables (Type‑C to C and Type‑A to C). It works with Windows, macOS, Linux, and other systems like TrueNAS or Unraid without extra setup. This makes it simple to install and use even if you’re not highly technical.

4. Expandable NAS Integration

Although primarily a DAS enclosure, the D4‑320U can connect to a TerraMaster NAS device running TOS 5.1 or later and be used to expand the NAS’s storage pool or create additional storage arrays. This lets you grow your NAS capacity without buying a new unit — useful for business environments where storage needs increase over time.

5. Intelligent Power & Drive Protection

The device includes built‑in safeguards to protect your drives:

• Power protection circuitry guards against incompatible voltages or surges that could damage disks.

• Power‑on recovery memory lets the device automatically restart after a power outage, so you don’t have to manually power it up every time — especially helpful in server environments.

• Smart drive sleep mode reduces wear and power draw by spinning down idle drives, extending their lifespan and saving energy.

 6. Efficient & Quiet Cooling System

Inside is an intelligently regulated fan system with dual‑ball‑bearing fans that automatically adjust speed based on drive temperature. This keeps drives cool during heavy use — important for reliability and performance — while minimizing noise. The design also improves airflow and reduces vibrations, making the unit suitable in quieter office or studio environments.

7. Rack‑Mountable, Space‑Saving Design

The D4‑320U is built in a 1U rack‑mountable chassis with a shallow depth — meaning it takes up minimal space in standard server racks. It can also be installed in wall‑mounted racks or compact server closets without needing extra rail kits. This helps professional setups keep things organized and efficient.

8. Supports Multiple Drive Types & File Systems

You can install both 3.5″ HDDs and 2.5″ HDD/SSD drives, giving flexibility depending on whether you prefer high‑capacity, economical storage or faster SSD performance. The enclosure also supports a wide range of file systems (NTFS, APFS, FAT32, EXT4, exFAT), meaning it can fit into nearly any workflow or system setup you use