Pros & Cons
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- Swift performance with our bank of test drives
- AI-powered search and photo management
- Tool-free drive sleds
- Wide array of connectivity, including multiple USB ports and SD card slots
- Spiffy front-panel LCD readout
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- Only one multi-gig LAN port, and one M.2 slot
- Like most modern multi-bay NAS, drives are not included
- App catalog selection is thin
Zettlab D4 Specs
| Bay Size | 2.5 and 3.5-inch |
| Connection Type | 1GbE |
| Connection Type | 2.5GbE |
| Connection Type | HDMI |
| Connection Type | USB 2.0 (2) |
| External USB Hard Disk Expansion | |
| Hard Disk Configuration | RAID 5 |
| Media Server | |
| Network Medium | Wired |
| Number of Bays | 4 |
| Printer Server | |
| Rack-mount or Standalone | Standalone |
| RAID Level | Basic |
| RAID Level | JBOD |
| RAID Level | RAID 0 |
| RAID Level | RAID 1 |
| RAID Level | RAID 10 |
| RAID Level | RAID 5 |
| RAID Level | RAID 6 |
| Remote Access | |
| UPnP Capable | |
| Wired Network Speed | 10/100/1000/2.5GbE |
The Zettlab D4 AI NAS is a four-bay network-attached-storage (NAS) drive built to handle a bunch of jobs: 4K media streaming hub, backup repository, and personal cloud server. To tackle all that work, the unit packs an eight-core CPU, AI-powered productivity and data-management tools, a nice spread of USB ports, and even twin SD card readers. It's a breeze to set up, and it delivers very fast performance in our testing. And you can snap it up for $699.99—not terribly expensive for a four-bay NAS, and it's often discounted. But you have to consider the negatives, too: The D4 has only one multi-gig Ethernet jack and a single M.2 slot, and it's short on apps. If you need a beefier four-bay NAS with way more multi-gig LAN ports and M.2 slots (four of each!), and a massive selection of apps, check out our Editors’ Choice winner, the Asustor Lockerstor 4 Gen 3 (AS6804T). But be prepared to pay about twice as much, possibly more.
Design: Decked Out With Ports
Clad in an all-black enclosure, the D4 measures 7.2 inches high, 8.2 inches wide, and 9.2 inches deep.
(Credit: Joseph Maldonado)Zettlab packs a lot of features up front. On the device's face, you'll find four tool-free drive sleds, a pair of SD card slots (SD4.0 and TF4.0), two USB 3.0 ports (one Type-A and one Type-C), and a one-touch copy button. To the left of the ports, a 3.5-inch LCD readout shows the D4’s IP address, CPU and memory usage, storage capacity, and the current time. You also get status indicators for all four of the installed hard drives and the M.2 drive, if any.
(Credit: Joseph Maldonado)Around back, the machine's rear panel houses 2.5GbE and 1GbE LAN jacks, two USB 2.0 Type-A ports, and an HDMI video port. (You also get a removable magnetic dust cover.) For comparison, the more expensive Asustor AS6804T gives you a pair of 10GbE ports, two 5GbE ports, three USB 3.2 Gen 2 Type-A ports, and a pair of 40Gbps USB4 Type-C ports.
(Credit: Joseph Maldonado)Inside the enclosure, the D4 packs in an eight-core Rockchip RK3588 CPU, 16GB of DDR4 RAM, and 32GB of flash memory. You can install up to 100TB of storage using four 24TB platter drives and a 4TB M.2 SSD—but bear in mind that you get only one M.2 slot. Some other NAS devices, such as the Synology DiskStation DS425+, typically give you at least two; the Asustor AS6804T offers four.
(Credit: Joseph Maldonado)The D4 supports a range of RAID configurations—JBOD, Basic, RAID 0, RAID 1, RAID 5, RAID 6, and RAID 10—as well as the Btrfs file system. The unit's drive sleds can handle either 2.5- or 3.5-inch drives. (And remember, as with nearly every multi-bay NAS we review, the D4 doesn't come with storage drives. You'll need to supply your own.)
Software: AI Augmented, But Light on Apps
The D4 uses the company's own ZettOS operating system, which you can access via a web console or a mobile app. The software lets you handle basic NAS tasks—such as permission management and file and folder creation—but it also includes AI-powered features.
With AI Search, you can hunt for photos, videos, and documents using natural-language entries, and Knowledge QA lets you ask questions and receive answers based on your stored data. The Photo Album, meanwhile, uses AI to categorize and index photos and videos, and the Auto Transcription and AI Clip features convert conversations from work meetings, classroom lectures, and personal recordings into text notes.
(Credit: Zettlab/PCMag)The web console provides a desktop interface with a search bar at the top for AI Search and a launch bar at the bottom with icons for App Store, ZettAI, Files, Settings, CoCard, Clip, and Photos. The App Store is exactly what it sounds like: a clearinghouse for downloadable apps that let you use the NAS as a backup solution, a media server, a cloud server, a Docker platform, and more. As of this writing, though, it served up only 41 apps—positively skimpy next to the 256 that you can draw from Asustor's app store for its Lockerstor 4 Gen 3 (AS6804T).
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(Credit: Zettlab/PCMag)The ZettAI icon opens a screen where you can use AI to search for content on the NAS and let AI set up the NAS for you. Tapping the Files icon lets you create and share folders, set up user teams with specific access privileges, and tag specific files. With Settings, you can handle a variety of tasks, such as creating storage pools, checking drive health, and configuring fan, light, and display settings.
You can hit the CoCard icon to create automated and manual backup tasks, and click on Clip to manage and edit video files locally rather than in the cloud. Finally, Photos lets you organize and manage your photo and video files.
Installation and Setup: Taking Easy Street to RAID
Modern NAS devices are usually a breeze to install, and the D4 sticks with the program. To get the NAS up and running, I mounted four of our standard test 10TB Seagate IronWolf drives into the trays, slid them home, connected the NAS and my desktop PC to a 2.5GbE switch, and powered everything up.
Next on the agenda: a trip to the Zettlab website, where I snagged the Zettlab app for Windows. (You can also get iOS, Android, macOS arm64, or macOS x86 versions.) I opened the program, registered the NAS, created an account, and waited a minute for the device to initialize.
After that came some more basics. I created a storage pool and selected RAID 5, and ended up with a total storage capacity of 26.9TB. The pool initialized in five minutes, and it took 20 hours to synchronize. The NAS was ready to go.
Performance Testing: Rev Up the Platters
The D4 delivered very fast performance on our file-transfer tests, in which we time read and write speeds while transferring a 4.9GB folder containing a mix of music, video, photo, and office document files between the NAS and a desktop PC on the same network.
The D4 led the pack with a write score of 289MBps, just edging out the Synology DiskStation DS425+ at 282MBps and the Asustor AS6804T at 283MB; the D4 delivered a wider margin over the QNAP TS-432X-4G and its 245MBps score.
On the read test, the D4 garnered 298MBps, besting the Synology DS425+ (282MBps), the QNAP TS-432X-4G (272MBps), and the Asustor AS6804T (283MBps).
Final Thoughts
Zettlab D4 AI NAS
The Zettlab D4 AI NAS is a four-bay network-attached-storage device that delivers snappy performance alongside AI-powered search and photo management features. Just mind the app store: It doesn’t offer a lot of choices.