Miscellaneous Aspects and Concluding Remarks

The performance of the three different Crucial X10 Pro PSSDs in various real-world access traces as well as synthetic workloads was brought out in the preceding sections. We also looked at the performance consistency for these cases. Power users may also be interested in performance consistency under worst-case conditions, as well as drive power consumption. The latter is also important when used with battery powered devices such as notebooks and smartphones. Pricing is also an important aspect. We analyze each of these in detail below.

Worst-Case Performance Consistency

Flash-based storage devices tend to slow down in unpredictable ways when subject to a large number of small-sized random writes. Many benchmarks use that scheme to pre-condition devices prior to the actual testing in order to get a worst-case representative number. Fortunately, such workloads are uncommon for direct-attached storage devices, where workloads are largely sequential in nature. Use of SLC caching as well as firmware caps to prevent overheating may cause drop in write speeds when a flash-based DAS device is subject to sustained sequential writes.

Our Sequential Writes Performance Consistency Test configures the device as a raw physical disk (after deleting configured volumes). A fio workload is set up to write sequential data to the raw drive with a block size of 128K and iodepth of 32 to cover 90% of the drive capacity. The internal temperature is recorded at either end of the workload, while the instantaneous write data rate and cumulative total write data amount are recorded at 1-second intervals.

Sequential Writes to 90% Capacity - Performance Consistency
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The 4TB version can sustain around 1600 MBps for the duration of the test, while ending up at 70C. On the other hand, the 2TB version starts out similarly but drops down to 1300 MBps after around 10 minutes. Both the 1TB and 2TB versions ended up around 65C. However, the 1TB variant dropped down from 1600 MBps to 1200 MBps within a few seconds of starting the test. The reason for this is likely to be the history of write accesses putting the controller in a rather fragile state, rather than thermal throttling.

Power Consumption

Bus-powered devices can configure themselves to operate within the power delivery constraints of the host port. While Thunderbolt ports are guaranteed to supply up to 15W for client devices, USB 2.0 ports are guaranteed to deliver only 2.5W (500mA @ 5V). In this context, it is interesting to have a fine-grained look at the power consumption profile of the various external drives. Using the ChargerLAB KM003C, the bus power consumption of the drives was tracked while processing the CrystalDiskMark workloads (separated by 5s intervals). The graphs below plot the instantaneous bus power consumption against time, while singling out the maximum and minimum power consumption numbers.

CrystalDiskMark Workloads - Power Consumption
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The average power consumption during the active stage is around 2W, compared to the 3W idling number for the best overall performer of them all - the SanDisk Extreme Pro v2. When operating with battery-powered devices, the Crucial X10 Pro is undoubtedly an excellent choice.

Final Words

The flash market is currently experiencing a supply glut, with pricing to the advantage of the consumers. Crucial launched the 4TB version of the X10 Pro at '$290, and the pricing has held steady since then. There is a slight premium over the X9 Pro, but that is only to be expected for the performance jump. At 7.25¢ / GB, the PSSD presents excellent value for money. Other capacity points come in at '$169 (8.5¢/GB) and $120 (12¢/GB) . The 1TB variant's performance consistency is not as good as expected - the 2TB and 4TB versions present a better value proposition.

The bridge-based PSSDs presented as comparison units are more of a premium offering, though we see the much-maligned SanDisk Extreme Portable v2 being priced as low as $300. From a pure performance viewpoint, it is hard to recommend against the SanDisk PSSD if the 3-2-1 backup strategy is being observed. However, the X10 Pro SKUs score in the power consumption and physical footprint aspects. Crucial is also throwing in some value-adds such as the Mylio Photos+ trial subscription into the mix. Overall performance across a variety of workloads may not favor the X10 Pro SKUs when bridge-based PSSDs are in the picture. However, for the vast majority of direct-attached storage use-cases, the performance profile, physical footprint, case design, and pricing of the 4TB and 2TB Crucial X10 Pro SKUs represent an optimal combination. The 1TB version can be recommended for entry-level use-cases, but needs to be priced a bit lower keeping its performance consistency issues in mind.

 
Performance Benchmarks
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  • SanX - Friday, November 10, 2023 - link

    Time for 40gbit/s devices and USB4. They are already sold on Amazon, though price is a bit too high around $120-150.
    As to the disks of this article -- all they show good numbers in CrystalDiskMark but in reality 10Gbit/s devices will show transfer/copy data speeds like current harddrives 250MB/s , and 20Gbit/s ones like the older serial SSDs (500MB/s), which is hell slow and annoying. after you have seen speeds of NVMe on PCIe 4.0 around 3 GB/s, and PCIe5.0 probably get you double that
  • Jansen - Friday, November 10, 2023 - link

    8TB version would be great. Let’s encourage larger capacities please.
  • linuxgeex - Friday, November 10, 2023 - link

    I think the author is imagining that non-mainstream users buying USB external disks are going to use them for mission-critical high-IOPS DB write workloads such that they can actually wear out the QLC storage with an abundance of writes, and simultaneously they have forgotten that today's QLC has the same TBW ratios as early eTLC drives, which as the name suggests, was used in Enterprise.

    In reality even professional users won't be subjecting an external SSD to punishing high-IOPS write workloads. They will write maybe 200GB in a day, and a 600TBW rating will last them 10 years.
  • FunBunny2 - Saturday, November 11, 2023 - link

    today's QLC has the same TBW ratios as early eTLC drives, which as the name suggests, was used in Enterprise.

    well... Enterprise use cares not about longevity, only that those XX,000,000 drives they bought don't fail before the warranty claims. Enterprise backs up at fetish levels, and swaps out devices just before warranty use is reached. if a QLC SSD is ten cents cheaper than a TLC drive in the same warranty period, they'll buy it. if the QLC has a 3 year warranty and the TLC a 5 year warranty, and the QLC is $X cheaper, then Enterprise will load up; otherwise not.

    consumer-users, generally, just don't behave that way.
  • Hresna - Saturday, November 11, 2023 - link

    What’s the explanation for the wildly different write bandwidths based on file type? I’m aware of performance penalties for trying to write lots of small files versus large ones, but I would think that video writing and iso writing should be pretty similar as a workload.

    A practical and “mission critical” use case for high write speeds is recording high bitrate video direct from camera… if you start dropping frames, the device is essentially useless in a professional setting. Camera data rates are getting hunger and higher with intraframe and raw 6k / 8k becoming more common.
  • wr3zzz - Sunday, November 12, 2023 - link

    I stop shopping for portable SSD faster than 800MB/s after realizing the time I spent trying to get the right port for maximum speed is more than the time saving I could get from a theoretically faster but certainly more expensive portable SSD.
  • MDD1963 - Thursday, November 16, 2023 - link

    "Booting Windows 10

    The read-write bandwidth recorded for each drive in the *boo* access trace is presented below."

    Boo access is important! :)
  • GreenReaper - Tuesday, November 21, 2023 - link

    Go for the ICs, Boo - go for the ICs!

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