USB 3.2 Gen 2x2 State of the Ecosystem Review: Where Does 20Gbps USB Stand in 2020?
by Ganesh T S on October 5, 2020 10:30 AM EST- Posted in
- Storage
- SSDs
- Western Digital
- SanDisk
- ASMedia
- USB 3.2 Gen 2x2
Device Features and Characteristics
A quick overview of the internal capabilities of the storage devices is given by CrystalDiskInfo. The drive information doesn't change based on the host. This also serves to verify that S.M.A.R.T access (and despite not being mentioned explicitly, TRIM support also) is available irrespective of the port that the drives connect to.
| Drive Information |
 |
CrystalDiskInfo confirms the internal SSDs being used in the WD_BLACK P50 and the SanDisk Extreme PRO Portable SSD v2 to be the SN750E and SN730E respectively. Prior to looking at the usage characteristics of the various drives, it is helpful to compare their specifications and also take a look at the internals.
| Direct-Attached Storage Characteristics | ||
| Aspect | ||
| Upstream Port | USB 3.2 Gen 2x2 Type-C | USB 3.2 Gen 2x2 Type-C |
| Bridge / Controller | ASMedia ASM2364 SanDisk 20-82-007011 |
ASMedia ASM2364 SanDisk 20-82-007011 |
| Flash | SanDisk BiCS 4 96L 3D TLC | SanDisk BiCS 3 64L 3D TLC |
| Power | Bus Powered | Bus Powered |
| Physical Dimensions | 57.34 mm x 110.26 mm x 10.22 mm | 62 mm x 118 mm x 14 mm |
| IP Rating | IP55 | N/A |
| Weight | 85 grams (without cable) | 115 grams (without cable) |
| Cable | USB 3.2 Gen 2x2 Type-C to Type-C USB 3.2 Gen 2 Type-C to Type-A (30cm each) |
USB 3.2 Gen 2x2 Type-C to Type-C USB 3.2 Gen 2 Type-C to Type-A (30cm each) |
| S.M.A.R.T Passthrough | Yes | Yes |
| UASP Support | Yes | Yes |
| TRIM Passthrough | Yes | Yes |
| Encryption Support | Hardware (SanDisk SecureAccess App) | N/A |
The key difference is that our review samples have a SN750-class NVMe SSD equipped with 64L 3D TLC in the WD_BLACK P50, and 96L 3D TLC in the SanDisk Extreme PRO v2. The former doesn't have hardware encryption enabled (and even software encryption with the WD Security app is not available). The latter uses the SanDisk SecureAccess App to activate the hardware encryption.
The teardown galleries above shows the significant amount of thermal design in both drives. The presence of the ASMedia ASM2364 bridge chip in both drives is also confirmed. The SanDisk Extreme PRO has a significant chunk of aluminum directly in touch with the thermal pad / covering for the heat-generating components of the internal boards. A clasp is also seen on the Type-C port to help achieve the IP55 rating. In contrast, the WD_BLACK P50 appears over-engineered with a large number of thermal pads, a separate aluminum heat-sink, and a thermal pad on top of that heat sink. Since the underside of the P50 is plastic, a metal flap is also placed between it and the internal SSD assembly. Overall, the thermal design appears fairly effective, and its evaluation report is provided in a subsequent section.
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repoman27 - Wednesday, October 7, 2020 - link
According to the USB4 spec, host-to-host tunneling is possible via inter-domain links even when using a hub, but of course YMMV.Thanks for pointing out that Thunderbolt 4 hub, that's awesome! And way cheaper than I was expecting. It looks like a Goshen Ridge hub based on Intel's Thunderbolt 4 Compact Dock reference design to me. However, I'm a little worried that OWC's wording implies that it is not backwards compatible with Thunderbolt 3 hosts. That would seem insane, and it may just be an OS support issue at this juncture, but it sure sounds like it's for Thunderbolt 4 PCs only. Aargh!
CaptainChaos - Wednesday, October 7, 2020 - link
It *might* work, and cost may not be prohibitive & worth a shot! I don't see networking mentioned at all on the product page. Also, aren't thunderbolt 3 cables required to be active to do 40GB speeds?CaptainChaos - Wednesday, October 7, 2020 - link
... plus it's described as a hub and not a switch so expectations would need to be tempered accordingly!repoman27 - Wednesday, October 7, 2020 - link
IP over Thunderbolt is a thing, but you'll never see it advertised. Much like IP over IEEE 1394 (a.k.a. FireWire) was also a thing... that nobody knew about. Where we're going, we don't need Ethernet!It is a Thunderbolt 4 / USB4 hub, almost certainly based on the recently launched Intel JHL8440 chip. Per the USB4 spec, it contains a router which "includes a flat point-to-point, configurable switch necessary to create the internal paths between adapters", in addition to a PCIe switch as well as USB 3.2 and USB 2.0 hubs. It is also required to support Thunderbolt 3 interoperability and DisplayPort Alternate mode on all downstream facing ports. It's the real deal.
repoman27 - Wednesday, October 7, 2020 - link
Oh, also, the max length for passive cables at 40 Gbit/s is 0.8 m, and FWIW Apple sells theirs for $39. Full featured active cables are available in lengths up to 2.0 m, but cost $129 (from Apple).And throughput for host-to-host communications will be limited by the available bandwidth of the PCIe link between the host CPU and Thunderbolt controller. For Thunderbolt 3 hosts, that tends to be a PCIe Gen3 x4 link which results in real-world throughput of about 22 Gbit/s after accounting for protocol overhead.
So Thunderbolt isn't exactly going to be a panacea, but if you can live with those constraints, it is still a very fast interface.
CaptainChaos - Wednesday, October 7, 2020 - link
i want one (or 2 - wonder if they can be cascaded?)! Should be interesting to see follow ons from this or other vendors for cost or features. I've been eyeballing the 2.5baseT switch recently released by QNAP but this might be a better option for me.CaptainChaos - Wednesday, October 7, 2020 - link
... except that I guess I'd need to use a PC to bridge TB subnet to a 10 GB ethernet network :-(Deprectuod - Saturday, October 10, 2020 - link
It looks good!xpclient - Tuesday, October 13, 2020 - link
Hi Anandtech, can you do a performance comparison of 2 PCs networked via Thunderbolt 3 to Thunderbolt 3 standard cables (since it allows running 10Gbps Ethernet) vs networking using USB 20 Gbps (Gen 2x2) to RJ-45 10 Gbps Ethernet adapters between 2 PCs? Which is faster? I bet the Thunderbolt 3 connection will be faster due to the protocol overhead of USB.Howard - Sunday, October 18, 2020 - link
With the stupidity (or anti-consumerist behavior) so glaringly obvious, It's almost as if USB-IF want people to stick with Lightning for as long as possible.