TerraMaster D4 SSD review: Palm-sized DAS with up to 32TB of storage over USB4

TerraMaster is back with another disk enclosure. I was offered the chance to take a look at their new D4 SSD, which is a palm-sized DAS that supports four M.2 SSDs ahead of its launch, today, on June 17.

This follows our review of the all SATA D9-320 that we did last month, and the D5 Hybrid and D8 Hybrid, both of which are essentially multi-disk (HDD and SSD) enclosures for external backup, or to expand the capacity of a NAS.

Here are the full specs of it:

First, I should mention that TerraMaster initially only put SINGLE DISK support in the RAID specification on their product page, however unlike the D9-320 9-bay HDD enclosure, I was surprised to see that it actually supports both Striped and Spanned volumes in Windows 11, so you can get RAID1 in Windows 11 with this if you wanted, or simply combine all of the available drives into a single volume spanning the size of all drives combined. The specifications page has since been updated with full RAID support, but this is limited to connecting the D4 SSD to a TerraMaster NAS in our own tests.

Technically, it is only SINGLE disk support if you plan to connect it to any NAS other than a TerraMaster one. Because it connects over USB, this means you will only be able to create usbshares, not storage pools, but maybe other brands support RAID over USB, feel free to comment with your experience. However, it is a nice surprise that Windows supports more functions with this D4 SSD than a NAS offers, which may also result in how you decide to use it.

Also, for some reason, they have put that it weighs 600 grams. I think this is the package weight, because I weighed the D4 SSD after putting in three SSDs, and it came to 419 grams, which is really light!

What's in the box

• D4 SSD device
• USB Type-C cable (C to C) 0.8m
• Power adapter
• Quick installation guide
• Limited warranty notice
• Bag of 2x M.2 screws

I should mention that the "Quick Installation Guide" is simply a card with a QR code that links to https://start.terra-master.com. It requests your email and product details, which then opens to a full online User Guide. After getting to the end of the online User Guide (17 pages), which frustratingly encountered really slow page loads at times, there's a link to download a PDF of the User Manual.

Design

The design of the D4 SSD matches that of the F8 SSD Plus that I reviewed last year; in fact, it shares almost the same dimensions, but is 3.7cm shorter than its full NAS SSD counterpart, which is another example of how TerraMaster disk enclosures closely match their NAS sibling.

It is essentially a metal frame with what I would call a matte black plastic cover. It is a bit of a dust and fingerprint magnet, too, but a quick wipe, and it's all gone, unlike what you would see with a glossy plastic exterior. It has a slightly textured feel to it and definitely feels premium, but also not in such a way that it would easily slip out of your hand.

On the front, the D4 SSD is completely bare aside from a small sticker with D4 SSD printed on it; both sides are the same, with the TERRAMASTER logo stamped in the center. Unlike the D5-, D8 Hybrid, and NAS' in the same class (2- and 4-bay,) the logos do not double as ventilation on the D4 SSD.

Around the back is a pretty bare affair with regulatory information stamped on it, then you have the Type C USB4 port and barrel power port input along with the screw that once removed, lets you slide off the cover to access the internals and manage the M.2 SSDs.

The top uses the full surface area aside from the power button to assist with ventilation, and on the bottom, there are two 50 x 50 x 10mm intake fans that are very quiet.

Installation

Well, like the D9-320, there's hardly anything to it. Take off the screw around the back and screw in your PCIe NVMe M.2 2280 SSDs. They run at a (combined) max speed of USB4 (40 Gbps). TerraMaster includes a screw on each M2 connector, so need to go hunting, there are also two "backup screws" included in the box.

For our review, we used two MP44Q 4TB NVMe SSDs ($224.99 on Amazon or Newegg) that TEAMGROUP supplied us with, and a 2TB Rocket 4 Plus ($219.99 on Newegg) that Sabrent sent to us. They are all PCIe 4.0 x4 drives.

TerraMaster also uploaded a video to YouTube that shows how to install the storage options.

Usage

First, a bit of background on the capabilities of the D4 SSD. The ASMedia ASM2464PDX chip offers four lanes at PCIe 4.0 x 1; however, you can only expect to see up to 3257 MB/s speeds, and that will need to be in a RAID configuration; it basically translates to speeds you would expect from a traditional PCIe 3.0 SSD. This drops to around half that speed if the disks are being used independently in SINGLE disk mode.

Here is how TerraMaster breaks it down:

Unlike the D9-320 that we recently tested, it is not possible to daisy chain the D4 SSD with multiple units. As of writing, TerraMaster is not offering it in any other sizes (so, there is no D8 SSD option).

RAID

Happily, you can create a Striped or Spanned Volume of the disks in Windows, but be aware that it will only combine the total size of the smallest-sized SSD (so if you have 2TB + 4TB + 4TB, a volume of 3x 2TB will be created).

In TOS 6 the same is true with the default TRAID setting, which is basically TerraMaster's own flavor of RAID5.

Yes, it is possible to create full storage pools in TOS 6 connected over USB to a TerraMaster NAS. I tried this in Synology DSM 7.2 but I could only create single disk USB shares. Creating a 3.71TB Storage pool (using two 4TB SSDs in TRAID) in TOS 6 (on a F4 SSD) took around three hours to synchronize.

On the official website, it is suggested that you download TPC Backupper, which is not included in the box, on a USB or onboard storage in the D8 Hybrid. There's a card that also instructs to download TPC Backupper. Still, I find that a bit of a shame because even most Razer or Logitech keyboards and mice include the setup program for Synapse or Logitech Options when you connect these devices to your Windows PC.

Upon installing TPC Backupper by AOMEI a web page automatically opens in the default browser, thanking for a successful installation of what is actually a rebranded version of the free AOMEI Backupper Standard, and it "helpfully" suggests upgrading to a paid version for more features. The nag to upgrade to a paid version of the software seems a bit desperate if you ask me.

I decided to emulate a daily backup that I usually do with the excellent SyncFolder, which basically backs up my Documents and Pictures folders from my main PC to my NAS Cloud drive. For this, I used the TPC Backupper app that I mentioned earlier.

D4 SSD attached to local PC, local disk backup to D4 SSD over USB

The process took a little under ten minutes to back up 34,979 files in 2,213 folders totaling 35,7GB into an .afi image file on a Striped volume. Restoring to the same local SSD only took 2m30s, which is impressive.

D9-320 attached to local PC, backup to NAS over network

Next, I backed up the same Documents and Pictures folders from the Striped volume in the D4 SSD to my Cloud backup over the network, and this took 11m20s. Restoring to the D4 SSD took just under three minutes, which is only half a minute longer than restoring the same data locally.

Local PC backup over LAN to D4 SSD attached to NAS over USB

Lastly, I ran the backup with the D4 SSD attached directly to my TerraMaster F4-424 Max over USB, so this meant copying the Documents and Pictures folder from my local PC over my LAN to the D4 SSD.

The process took 14m33s to back up 34,979 files in 2,213 folders totaling 35,7GB into an .afi image file on the Simple volume, which is a little longer over the network than with the D4 SSD attached via USB to my local PC. Restoring the data locally over the network only took 1m30s, which was a minute quicker than restoring from the D4 SSD when attached locally, for some reason.

Drive speed

However, back to the drive setup, I ran CrystalDiskMark 8.0.5 in Windows 11 24H2 with the D4 SSD attached to that PC. I included both RAID and SINGLE disk mode, and the results definitely align with TerraMaster's drive speed claims, mentioned earlier in this review.

I tried to measure the noise, but it did not register over the (roughly) 50dB of ambient noise of my work-from-home office. We will have to take TerraMaster's word for the claim about noise levels being as low as 19 dB.

Conclusion

TerraMaster markets the D4 SSD as "specifically designed for media creation and video production applications," but also says that it "serves as an ideal external storage expansion solution for Mac mini and can be used as a Mac OS boot drive." Sorry, but I do not have a Mac mini to test this claim.

TerraMaster also claims that this would suit gamers, for its "seamless experience indistinguishable from running on a local drive, with truly zero-latency performance." So it really has several use case applications depending on your wishes, and affordability to populate with up to four (large) SSDs.

It looks premium, but it is what it is, essentially a plastic shell of a DAS. But it does not feel cheap either, the bottom intake fans are quiet, and overall, it is a nice-looking device that will not take up much room anywhere you place it. The added bonus here is RAID support, unlike with the D9-320 in Windows. However, do not expect RAID support on any NAS other than TerraMaster's own TOS 6 because you cannot create a storage pool over USB (at least in Synology DSM).

Say you had a few one- or two-terabyte SSDs lying around, you could stick them all in and create a striped volume for anything up to 8TB for a really large storage volume in Windows.

If I had any complaints at all, it would be how it does not really fully support 3rd party NAS' for creating a storage pool, but that would probably require an eSATA port. Secondly, I would have preferred to have seen a toolless method for installing and managing the SSDs. Most modern motherboards now use the toolless method of a clip or latch for M.2 SSDs, and given that the D4 SSD only supports 2280-sized SSDs, I don't feel this is a huge ask.

You can purchase the TerraMaster D4 SSD for $299.99 from today (June 17) on Amazon.

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