Device Features and Characteristics

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. All the drives discussed in this review adopt the strategy of placing a NVMe SSD controller behind a USB 3.2 Gen 2 bridge chip.

Direct-Attached Storage Characteristics
Upstream Port USB 3.2 Gen 2 Type-C USB 3.2 Gen 2 Type-C
Bridge Chip ASMedia ASM2362 ASMedia ASM2362
Power Bus Powered Bus Powered
Physical Dimensions 85 mm x 57 mm x 8 mm 96.2 mm x 49.6 mm x 8.9 mm
Weight 58 grams (without cable) 79 grams (without cable)
Cable 30 cm USB 3.1 Gen 2 Type-C to Type-C
30 cm USB 3.1 Gen 2 Type-C to Type-A
25 cm USB 3.1 Gen 2 Type-C to Type-C
25 cm USB 3.1 Gen 2 Type-C to Type-A
S.M.A.R.T Passthrough Limited Limited
UASP Support Yes Yes
TRIM Passthrough Yes Yes

The table above shows that the Samsung Portable SSD T7 Touch is the lightest of the new lot, coming in at 58 grams. In contrast, the Crucial Portable SSD X8 and the OWC Envoy Pro EX USB-C come in at 148g and 100g - both of them feel solid in hand with an aesthetically pleasing industrial design. The physical dimensions indicate that the Samsung Portable SSD T7 Touch and the Lexar SL100 Pro do not integrate a standard M.2 2280 SSD. Both are credit-card sized units and small enough to unobtrusively fit in any pocket.

The Lexar SL100 Pro Portable SSD uses a JMicron JMS583 bridge chip (just like the Plugable USBC-NVME enclosure). All the other SSDs in the new set use the ASMedia ASM2362 bridge. While all units support some sort of SMART passthrough, most of the traditional SMART monitoring tools can't reliably track the internal SSD's parameters over the bridge chip. TRIM support exists in allof the drives.

Samsung Portable SSD T7 Touch

Samsung's T7 Touch is a unique DAS, thanks to its fingerprint security feature. We had already covered various aspects of the drive in our launch piece.

Another key aspect of the T7 Touch is the availability of support for use with both PCs and smartphones - as in, Samsung provides mobile apps keeping the security aspect in mind. We had already covered this while reviewing the Portable SSD T5, and the T7 Touch can be used in the same way. On the hardware side, we find that the fingerprint recognition module is embedded in the inside of the casing. There is only one internal board which carries the MZBLQ product tag. The SSD controller is the S4LR033, and the ASMedia ASM2362 bridge chip is right next to it. The flash package has the K9DVGY8J5A tag, which decodes as: TLC, 5th gen V-NAND (92L), 512Gbit per die, 16 dies, 1TB for the whole package. This is the same NAND package used in 2TB 970 EVO Plus.

The thermal design also appears to tick all the right boxes - aluminum casing with a pink thermal pad (Samsung terms it as ePCM - encapsulated phase change materials) covering all the heat-generating PCB components. During operation, the LED around the fingerprint sensor lights up and rotates. The LED automatically turns off after the drive idles for 10 seconds. A blinking on/off status indicates that a security unlock is needed. All that said, it is possible to also use the T7 Touch as a dumb DAS without any of these security features activated.

SanDisk Extreme Pro Portable SSD

SanDisk's Extreme Pro Portable SSD carries forward the gumstick form-factor that has served the previous Extreme Portable SSD models well. The key difference is that the fully plastic enclosure in the previous generation is replaced by a combination of plastic and aluminum.

SanDisk is now supplying two distinct cables (Type-C to Type-C, and, Type-C to Type-A) with the Extreme Pro, compared to the Type-C to Type-C and Type-C to Type-A adapter scheme used in previous SSDs. Internally, we see a wrapper around the mainboard (with the ASMedia ASM2362bridge chip and a Type-C port that is also protected by a gasket to prevent water ingress) with a single thermal pad in it. A WD Black NVMe SSD acts as a daughterboard. SanDisk also claims IP55 ratings for dust and water resistance.

Lexar SL100 Pro Portable SSD

Lexar's SL100 Pro adopts the same single-board strategy as the Samsung T7 Touch, enabling it to come in a more compact form-factor compared to the gum-stick offerings. The SSD controller is from Marvell and the bridge chip is the JMicron JMS583.

While most other USB 3.2 Gen 2 SSDs claim speeds of up to 1050 MBps, Lexar is conservative and claims speeds of up to 950 MBps only.

Crucial Portable SSD X8

The Portable SSD X8 is the only device being considered today to come with QLC memory. The device places their Pl NVMe SSD behind an ASMedia ASM2362 bridge chip.

It comes with a single Type-C to Type-C cable and a bundled Type-C to Type-A adapter. The unit proved quite difficult to disassemble, and we do not have any teardown photos of the device.

OWC Envoy Pro EX USB-C

The OWC Envoy Pro EX USB-C is available either driveless, or, with an OWC Aura P12 NVMe SSD pre-installed. Our review version came with a 2TB P12.

The enclosure is fully metallic and the single thermal pad affixed to the casing along the length of the M.2 drive is good enough to draw away the heat generated in the course of usage.

Introduction Synthetic Benchmarks - ATTO and CrystalDiskMark
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  • lilkwarrior - Thursday, January 23, 2020 - link

    Seems pointless to not be Thunderbolt 3 or USB4.
  • avbohemen - Thursday, January 23, 2020 - link

    I wonder what the limit is in the atto/as-ssd iops test. All drives hit a limit of 23-25k 4kB iops (atto) or 32k 4kB iops (as-ssd).

    Throughput is not saturated with 4kB iops and the drives are different enough in other benchmarks.

    Is it a limitation of the usb/uasp protocol or the bridge chip, or something else?
  • avbohemen - Thursday, January 23, 2020 - link

    Sorry, I mean crystaldiskmark instead of as-ssd.
  • Soulkeeper - Thursday, January 23, 2020 - link

    The crucial looked like the winner untill I saw the Performance Consistency results. Horrible.
    Otherwise most the benchmark results, outside of this, seem very close for all the drives to me.
  • ganeshts - Friday, January 24, 2020 - link

    Exactly! And, dare I say, for most casual users, the Crucial drive actual works out well. It is only power users and tech-savvy folks who expect to 'torture' their external drives that need to watch out :) Unlike other review sites [ and I don't want to name any ;) ], our aim is to give the complete picture so that readers can make an informed purchase decision.

    To be honest, if I were to purchase a portable SSD for occasional periodic backups (say, 10 - 20 GB of data at a time), the X8 is actually a good candidate because of the pricing alone.
  • dcroteau - Thursday, January 23, 2020 - link

    What kind of fake data is that?
    An NVMe drive at 19 degree Celsius? Less than room temperature?

    They run notoriously hot and wouldn't be below 30C in any circumstances. They can go as high as 70C without a proper heat sink.

    Even with proper cooling, they will never be below room temp. 19C is very frisky for a room temperature.
  • ganeshts - Friday, January 24, 2020 - link

    It is winter here in CA and the room temperature in my lab is around 63F (as I rarely turn on the air-conditioning in the lab for winters - the benchmarking testbeds are operated remotely / headless).
  • Meteor2 - Saturday, January 25, 2020 - link

    My heating never goes above 19C. Put a jumper on and save the planet.
  • regsEx - Thursday, January 23, 2020 - link

    USB 3.2 Gen 2 is just rebranded USB 3.1. Actual USB 3.2 is Gen 2x2.
  • Tomatotech - Friday, January 24, 2020 - link

    I hope you understood that as I didn’t at all.

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