Hands on: Asustor Nimbustor 4 Gen2 AS5404T review

Asustor’s Nimbustor 4 AS5404T is a four-drive NAS enclosure aimed at demanding home users or small offices. It’s a performance-focused NAS thanks to the fairly muscular Intel Celeron N5105 processor and 4GB of RAM. At the back you’ll find two 2.5GbE ports, along with two of the NAS’s three USB-A 3.2 Gen 2 sockets – the other one is easily accessed at the front.

The NAS can mount up to four 3.5in or 2.5in SATA disks in various RAID configurations including RAID5, 6 and 10. Unusually, it also has four NVMe slots. You could configure the AS5404T with a four-SSD RAID5 volume, alongside a slower disk-based storage pool. Alternatively, you could use an SSD cache to accelerate disk performance, or compromise with one or two SSDs on cache duty and others serving as a fast volume.

You can upgrade the enclosure’s installed RAM up to 16GB, though you’ll have to remove the 4GB it comes with. If you need to add storage, you can do so with up to three Asustor AS6004U expanders, allowing for a total 16 disks. Asustor says this NAS can hit maximum read and write speeds of 599MB/sec, but you’ll need to be using both network ports for that.

We’re not wild about this unit’s physical setup: there’s tool-less access for 3.5in disks, but the caddies release with a horrific snapping sound that had us checking to confirm we hadn’t broken the catches. The caddy clips are hard to remove, too. You’ll need a screwdriver to open the case and access the NVMe slots, but the SSDs themselves simply clip into place.

We configured the AS5404T with four 1TB hard disks in a RAID5 array and two 1TB WD Black SSDs configured as a separate RAID1 volume. Unusually among modern NAS servers, Asustor’s operating system defaults to the EXT4 file system, though Btrfs is an option. This NAS insists on synchronizing new RAID1 arrays, but at least with our SSDs the process completed within an hour.

Connected via a single 2.5GbE connection, the AS5404T got off to an impressive start.

It performed strongly through the ATTO disk benchmark, recording much quicker data rates than 1GbE competitors. With 16KB and 2MB file operations, it also showed a clean pair of heels to 2.5GbE rivals from QNAP. Things were far less impressive with the PCMark 10 Data Drive benchmark, however, on which the AS5404T was one of a few NAS enclosures we tested to record an inexplicably low score. We always confirm real-world data speeds with simple Windows file copies, however, and here the AS5404T was supreme, managing 85MB/sec when writing 11GB of files.

Performance was consistent when we tested its SSD storage, giving near-identical ATTO results with an SSD volume, and again when using SSD caching. Cached disk write speeds increased slightly in our file-copy test, although read speeds actually went down a little. We also recorded similar performances when we reinstalled this NAS with two Synology 4TB disks.

Asustor’s ADM operating system is comprehensive and easy to use, though we did spot a couple of oddities in this test. Most significantly, the AS5404T couldn’t be browsed from either a Chromebook or our Windows 11 test PC unless we turned on SMB1, although its shares could be accessed without it – so long as we entered the drive path by name.

One of the Nimbustor’s strongest points is Asustor’s App Central, which at the time of writing offered an incredible 272 apps, spanning networking, surveillance, productivity and entertainment. If you’re chiefly interested in the latter, an HDMI port gives you a way to view multimedia content on an attached screen, but you can organize and serve photos or other media through the likes of Plex.

Don’t let this NAS server’s media talents put you off if you’re buying for business, however. With blistering performance even when configured with two disks, the AS5404T is a solid starting package for a small business with big plans. If your micro office goes macro, you can add more disks, accelerate it with SSDs, beef up the memory, and even connect another enclosure. It’s our Labs Winner.

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