External bus-powered storage devices have grown both in storage capacity as well as speeds over the last decade. Thanks to rapid advancements in flash technology (including the advent of 3D NAND and NVMe) as well as faster host interfaces (such as Thunderbolt 3 and USB 3.x), we now have palm-sized flash-based storage devices capable of delivering 2GBps+ speeds. While those speeds can be achieved with Thunderbolt 3, mass-market devices have to rely on USB. Read on for a detailed review of the various high-speed external SSDs targeting the mainstream market.


High-performance external storage devices use either Thunderbolt 3 or USB 3.2 Gen 2 for the host interface. Traditional SATA SSDs (saturating at 560 MBps) can hardly take full advantage of thebandwidth offered by USB 3.2 Gen 2. Last year, we took a look at a couple of NVMe to USB 3.2 Gen 2 enclosures from MyDigitalSSD and Plugable. Since then, we have had various leading vendors come out with their own solutions for this market segment. A steady stream of USB 3.2 Gen 2 external SSDs have been coming in to our lab over the last six months, with SanDisk's Extreme Pro Portable SSD and Samsung's Portable SSD T7 Touch (announced at CES) being the latest.

UL / Futuremark also updated their PCMark 10 benchmark with a storage bench recently. Our usual synthetic benchmarks - CrystalDiskMark and ATTO - have also had newer versions released since we last updated our benchmark suite for direct-attached storage devices in 2017. Over the winter holidays, we tweaked our evaluation suite and processed all the USB 3.2 Gen 2 SSDs that had come in over the preceding months through it.

The list of DAS units being reviewed today is provided below.

  • Samsung Portable SSD T7 Touch 1TB
  • SanDisk Extreme Pro Portable SSD 1TB
  • Crucial Portable SSD X8 1TB
  • DIY Plugable USBC-NVME and MyDigitalSSD SBX 1TB
  • Lexar SL100 Pro 1TB
  • OWC Envoy Pro EX USB-C 2TB

A quick overview of the internal capabilities of the storage devices is given by CrystalDiskInfo.

Drive Information

CrystalDiskInfo allows us insight into the internal drive without opening up the unit. The most interesting aspects to note include the fact that UASP is supported by all drives, and all except the Plugable USBC-NVME and the Lexar SL100 Pro support NVMe 1.3.

Testbed Setup and Testing Methodology

Evaluation of DAS units on Windows is done with a Hades Canyon NUC configured as outlined below. We use one of the rear USB Type-C ports enabled by the Alpine Ridge controller for both Thunderbolt 3 and USB devices.

AnandTech DAS Testbed Configuration
Motherboard Intel NUC8i7HVB
CPU Intel Core i7-8809G
Kaby Lake, 4C/8T, 3.1GHz (up to 4.2GHz), 14nm+, 8MB L2
Memory Crucial Technology Ballistix DDR4-2400 SODIMM
2 x 16GB @ 16-16-16-39
OS Drive Intel Optane SSD 800p SSDPEK1W120GA
(118 GB; M.2 Type 2280 PCIe 3.0 x2 NVMe; Optane)
SATA Devices Intel SSD 545s SSDSCKKW512G8
(512 GB; M.2 Type 2280 SATA III; Intel 64L 3D TLC)
Chassis Hades Canyon NUC
PSU Lite-On 230W External Power Brick
OS Windows 10 Enterprise x64 (v1909)
Thanks to Intel for the build components

Our evaluation methodology for direct-attached storage devices adopts a judicious mix of synthetic and real-world workloads. While most DAS units targeting a particular market segment advertise similar performance numbers and also meet them for common workloads, the real differentiation is brought out on the technical side by the performance consistency metric and the effectiveness of the thermal solution. Industrial design and value-added features may also be important for certain users. The reamining sections in this review tackle all of these aspects after analyzing the features of the drives in detail.

Device Features and Characteristics
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  • zebrax2 - Thursday, January 23, 2020 - link

    For the ATTO you can probably create 2 line charts, for bytes and IO, with the read having solid lines and writes using dashed lines and lighter colors for example.

    As for CDM something similar to the charts here

    Anyway this is only my suggestion. If you do decide to keep the current layout may I at least suggest to have the expand all options on all the benchmark (e.g. the ATTO and CDM results doesn't have this option)
  • mm0zct - Thursday, January 23, 2020 - link

    I agree that it's not helpful to have all the comparisons separate, hidden under pulldown (can we get consolidated comparison graphs please?), but I'd also be interested to see the T5 in here for comparison as a SATA based USB3.1 gen2 drive.
  • MScrip - Thursday, January 23, 2020 - link

    Exactly. It would be nice to include a comparison to Samsung's previous highly-regarded SSD... the venerable Samsung T5 drive.

    Whenever there is a new version of a device... it's customary to compare it to the previous generation.

    It appears that Anandtech is strictly comparing MVNe drives here. But it would still be helpful for T5 owners.
  • R3MF - Thursday, January 23, 2020 - link

    is it fair to say that if you want ssd file storage that requires sustained sequential writes to 90% of disk capacity then you won't actually lose much performance by going for a sata based solution over the shiny new usb>PCI3.0 4x nvme?

    i.e. all that pcie bandwidth tends to be useful only for bursty activity until the SLC/ram cache is exhausted and cannot sustain full bandwidth write speeds.
  • Billy Tallis - Thursday, January 23, 2020 - link

    Most high-end consumer NVMe SSDs can average at least 1GB/s for a whole drive write to their 1TB models. Several average 1.5GB/s or higher, even though they are still using TLC with SLC caching. So it's definitely possible to do far better than SATA-based portable storage, but it may require a higher class of NVMe drive than some portable SSDs use.
  • R3MF - Friday, January 24, 2020 - link

    thank you.
    recently bought a 2tb sata drive for storage.
    think i'll be happy with 540MB/s vs 80MB/s for a 2.5" portable, enough that i won't miss a doubling to 1GB/s too much.
  • AnarchoPrimitiv - Sunday, January 26, 2020 - link

    If you need the fastest performance and do not have a Thunderbolt 3 port, I'd recommend buying the newly released USB 3.2 Gen2x2 add in card released by Gigabyte if I remember correctly. It is capable of 20Gbps (so double the speed of these drives) and Western Digital just released their external P50 drive which can saturate the connection with sequential r/w at 2000MB/s. Or if you'd rather make a DIY solution with an enclosure, I believe Asmedia has released a bridge chip for USB 3.2 Gen2x2 so I'd expect enclosures to hit the market soon
  • HStewart - Thursday, January 23, 2020 - link

    One thing good about forthcoming USB4 is that Thunderbolt 3 will be full stream and prices of TB3 drives will be coming down.
  • Korguz - Thursday, January 23, 2020 - link

    maybe . but will intel still have to certify it ?? if so... that is a major hurdle for any TB device to be adopted and used....
  • Dragonstongue - Thursday, January 23, 2020 - link

    mehhh QLC (whatever want to call them) should be that much lower cost to consumer than prices I have seen as of late, likely save the company who makes them a whole whack per die (per drive) vs "regular" such as TLC certainly vs MLC and significant price difference vs the much prefered SLC design, overall has not dropped price as much as I would expect if I am to be completely honest, in other words, the makers want as many of them sold as possible to reap the RnD by making them in the first place, but at same time do not seem overly "keen" on putting on the shelves around the world at "ok" price point.

    That $169 easily becomes in the $240+ range most other places than USA which makes something that "seems" pretty reasonable price run into the area of "why bother when spinning rust is much much lower cost, even if slower"

    mehh is all I can personally say, though thank you for the review overall ^.^

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