Synthetic Benchmarks - ATTO and CrystalDiskMark

SATA SSDs behind a USB 3.1 Gen 2 bridge claim speeds of around 550 MBps. Crucial claims 540 MBps, and the ATTO benchmarks for the X6 back up those claims. Unfortunately, these access traces are not very common in real-life scenarios.

SATA-Class External Drives Performance Benchmarks - ATTO

The reads approach the SATA bandwidth limits, but the writes are held back by the DRAM-less nature of the SSD controller and the QLC flash - ATTO maxes out around 370 MBps for those types of transfers. The HP P600 fares much better, but the X6 is better than the ADATA SC680 (it must be kept in mind that we are comparing different capacity points).

CrystalDiskMark, despite being a canned benchmark, provides a better estimate of the performance range with a selected set of numbers. As evident from the screenshot below, the performance can dip to as low as 11MBps for low-queue depth random writes.

SATA-Class External Drives Performance Benchmarks - CrystalDiskMark

Most USB 3.1 Gen 2 drives with NVMe SSDs claim speeds of around 1000 MBps, as does the Crucial Portable SSD X8.

NVMe-Class External Drives Performance Benchmarks - ATTO

Here, we see typical USB 3.1 Gen 2 external SSD speeds - upwards of 900 MBps for writes, and close to 1GBps for reads. CrystalDiskMark provides a better estimate of the performance range with a selected set of numbers. As evident from the screenshot below, the performance can dip to as low as 31MBps for low-queue depth random reads.

NVMe-Class External Drives Performance Benchmarks - CrystalDiskMark

We see slightly better overall performance in the 2TB version compared to the 1TB one for these workloads. Compared to the SanDisk Extreme PRO v2 connected to a USB 3.2 Gen 2 port (the other recent 2TB SSD we have reviewed), the X8 falls slightly behind on the sequential workloads, though random reads are better. Most DAS workloads are of the former type.

Device Features and Characteristics AnandTech DAS Suite - Benchmarking for Performance Consistency
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  • mostlyfishy - Wednesday, October 21, 2020 - link

    UASP and TRIM support mean these look good for a boot device on the Raspberry Pi 4s! Reply
  • Meteor2 - Monday, October 26, 2020 - link

    Why would you pair a $35 SBC with a $300 SSD? Reply
  • MartenKL - Wednesday, October 21, 2020 - link

    No Samsung T7 or X5 in the comparison? Reply
  • ganeshts - Wednesday, October 21, 2020 - link

    X5 is a Thunderbolt 3 SSD - so I don't consider it here in the USB 3.2 Gen 2 category.

    For T7, we only reviewed the 1TB capacity, so the only non-2TB ones are either the same X8 family or the SSDs launched within the last two months. FWIW, T7 didn't impress us too much: https://www.anandtech.com/show/16120/sandisk-extre...
    Reply
  • Duncan Macdonald - Wednesday, October 21, 2020 - link

    What is the rated write endurance ? External SSDs are often used to transfer large amounts of data between machines - in this use case the TBW rating is important. Reply
  • wrkingclass_hero - Wednesday, October 21, 2020 - link

    Probably the most important spec... if it can only be filled 600 times that's a serious issue. Reply
  • RSAUser - Thursday, October 22, 2020 - link

    If it's not the main OS drive, it will probably last a lot longer, most SSD wear is the small temp files of the OS rather than file transfers.

    Most drives are rated at hundreds of TB, standards are something like 100TB for every 250GB, and I doubt anyone would hit 4000 cycles within a few years, and by that point it should play nicely and be read only.

    What I am more worried about is how long it can store data without being powered up, I have a couple of external HDD's that I haven't plugged in in years.
    Reply
  • Meteor2 - Monday, October 26, 2020 - link

    I too would like to know how stable SSDs are unpowered long-term. Reply
  • TheinsanegamerN - Monday, October 26, 2020 - link

    SSD and long term don’t belong in the same sentence. Guaranteed data integrity for NAND flash memory is measured in weeks. Hard drives are measured in months, but can typically go years.

    Our treasury found this out the hard way when the handful of laptops they bought with SSDs in them all failed to boot after sitting for 2 months. SSDs were fine, but the data integrity was not.

    If you want long term cold storage and tape is not an option stick with writable blu rays or external HDDs and plug them in once every few months
    Reply
  • MrCommunistGen - Thursday, October 22, 2020 - link

    For what it is worth, CrystalDiskInfo has had a bunch of updates since v8.3.2. There's a chance that the latest version (currently v8.8.9) might detect TRIM support on the X8. Reply

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