USB4 is a merger of the USB and Thunderbolt standards that we’ve been promising for some time. The specification is already ready its second revision. We had to wait for fast external SSDs, which on paper could greatly benefit from this development. They didn’t come around for long, until a couple of “USB4” external SSDs recently arrived in our testing lab. You can read how it works and why we write USB4 in quotes in this review.
Why do you want a USB4 SSD drive?
If you choose an external SSD, you will quickly get bogged down in the jungle of modern USB standards and clan and gigabit flying around you. In short, most external SSDs today use the USB 3.2 Gen2 standard, which effectively allows speeds of around 1GB/s. There are also Gen2x2 SSDs, which are twice as fast in theory, but there’s hardly any hardware to hook them up to. Sometimes I come across these ports on desktop motherboards, but on laptops you can usually search for a long time.
Another path you can go down is a Thunderbolt SSD. They can reach speeds of up to 40 Gb/s (5 Gb/s). Here, however, the plug-in paradox is exactly the opposite. Many laptops have Thunderbolt these days, but you’ll hardly find this port anywhere else. In addition, Thunderbolt SSDs have an annoying feature like no other Compatible with the previous generation with USB. If you have a device that doesn’t support Thunderbolt, you won’t be able to access your data, even at a lower speed.
USB4 is the solution to this problem on paper. It offers the speed of Thunderbolt, but is compatible with older USB standards.
This is how USB4 SSDs work
In general, an external SSD is simply an M. 2 SSD with its own controller connected to a bridge chip that translates the PCIe / NVMe signal to USB. However, official USB4 bridge chips still do not exist. Although the Thunderbolt specification has been released for a long time, in fact Intel is still the only manufacturer of controllers for peripherals such as SSDs.
If you look at the product information for the two external SSD drives, you’ll soon find hints as to how WD’s Chinese sub-brand Sandisk and Orico could solve it. When Orico uses the term USB4, SanDisk calls the Professional PRO-G40 a “dual-mode” SSD. The hardware can handle both USB 3.2 Gen2 and Thunderbolt, which practically amounts to the same full USB4 implementation, but still looks different when it comes to the controllers on the internal circuit board.
Once opened – with a Sandisk with a Torx mini screwdriver, with Orico just some lateral pressure with the help of a vice – it turns out that both SSDs have not one, but two bridge slats. Sandisk and Orico both use an Intel JHL7440 controller for Thunderbolt connectivity, but we also find a “normal” USB 3.2 Gen2 controller on their printed circuit boards. With Sandisk it’s an ASMedia ASM2362, with Orico a JMicron JMS583. In practice, the SSD first tries to establish a Thunderbolt connection and the USB controller acts as a backup if that fails. You’ll notice this because it takes a few seconds with a “normal” USB port before your computer will recognize the external SSD.
By the way, the Orico MTQ-40G, all-in-one USB4 High-Speed Portable SSD Series 40Gb/s, might sound familiar to you. He shares his Mondrian-like design with 10 Gb/s solid state drive We’ve tested it before from this manufacturer, although this variant is somewhat larger. Naturally, this faster version is much more expensive. The 2TB version we tested stands for 600 euros on Amazon.nl. For the 1 TB and 512 GB versions, which are also available, you will pay 360 and 220 euros, respectively.
Plastic “works of art” rim made of zinc alloy. The printed circuit board with the above-mentioned bridge chips is hidden inside. This composite M.2 SSD combines a Maxiotek MAP1202A-F1C controller, a PCIe 3.0 x4 controller for SSDs without large cache, with flash memory from Chinese manufacturer YMTC. So Chinese-made NAND, we don’t see that much. The complete overprint is: “YMC3G004Tb68CA1C0”. We suspect that “3G” means we’re dealing with a somewhat older 3D generation with about 100 layers, but public information on manufacturer part numbers is scarce. YMTC stands on the way newly On the US Export Control List.
Both sides of the PCB are passively cooled with a thin heatsink. Clips are attached to the SSD itself and the bridge controllers, respectively. This became apparent during a previously unimagined drop test, thankfully only after the tests were completed. It’s a weak point in this product’s drop resistance, as one of the heat sinks broke off in the process. This didn’t matter for SSD functionality—after all, SSDs can take a beating—but you did hear the heatsink move when I shook the SSD.
The external SSD comes with a 30cm USB-C cable, with an adapter to USB-A attached. The device measures 11.5 x 6.3 x 2.1 cm and, according to Orico, can achieve a transfer speed of up to 3100MB/s.
SanDisk Professional PRO-G40
Sandisk Professional is the new brand name for products previously marketed by WD under the G-Technology brand. As mentioned earlier, the WD PRO-G40 doesn’t explicitly call it a USB4 SSD, but rather a combination of Thunderbolt 3 and USB 3.2 Gen2. So WD specifies separate speeds for both standards: 2700MB/s read and 1900MB/s via TB3 and 1050MB/s and 1000MB/s respectively via USB 3.2 Gen2.
At 11.1 x 5.8 x 1.2 cm, the PRO-G40 is particularly slimmer than an Orico SSD and feels considerably more powerful. The outside is finished with a rubbery-feel silicone; The interior is made of aluminum and should help cool the SSD. WD has received the Sandisk Professional PRO-G40 certification for IP68 water and dust resistance, withstands drops of up to 3 meters and withstands pressures of up to 1814 kg. The included cable has USB-C on both ends; Adapter to USB-A is not included.
Needless to say, the PRO-G40 has an SSD of its own making. We know the WD Red SN700’s Sandisk fingerprint controller is 20-82-00705-A2, an NVMe SSD intended for use in NAS devices. Flash memory also comes from our own factories, but what exactly the “60627” fingerprint means remains our guess. Unlike the SSD Orico uses, this SSD has a large cache, in the form of Samsung’s DDR4 chip (K4AAG16-5WBMCRC).
The table below shows the main differences between the two USB4 SSDs.
|SanDisk Professional PRO-G40
|3100 MB / sec
|2700 MB / sec
|2800 MB / sec
|1900 MB / sec
|Zinc alloy, ABS plastic
|Silicone rubber, aluminum and polycarbonate
|11.5 x 6.3 x 2.1 cm
|11.1 x 5.8 x 1.2 cm
|512 GB: 219.99 euros
1 TB: 359.99 euros
2 TB: 599.99 euros
|1 TB: 380.61 euros
2 TB: 585.68 euros
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