Testbed Travails

Regular readers of our direct-attached storage reviews might have noticed that we upgrade our DAS testbed approximately every couple of years. It is important to keep the testbeds consistent across reviews of different storage devices so that the effect of the CPU, DRAM bandwidth, etc. remain the same across different runs of the benchmarks on different devices.

Our most recent update to the DAS testbed was in early 2019 - a move to the Hades Canyon NUC triggered by the inconsistent performance of the Alpine Ridge port in our Skylake DAS testbed. This inconsistency started showing up after we attempted a Thunderbolt firmware upgrade to enable eGFX functionality on the machine. Prior to the Skylake-based testbed, we were using a Haswell-based system. We opted against building a fresh DAS testbed with either the TRX40 or Z490 boards, as the imminent arrival of USB4 meant that we could again be forced to do an upgrade. A testbed change not only involves preparing a new machine - it also involves benchmarking older drives again (to the extent possible). We wanted to put this off as much as possible.

The Hades Canyon NUC, without PCIe expansion cards handling capability, was ruled out as a recipient of the Yottamaster C5. The initial plan was to use the Ghost Canyon NUC for this purpose after removing the discrete GPU. As we soon discovered, the PSU of the Ghost Canyon NUC doesn't come with SATA power cables, and an adapter cable wasn't handy. We moved on to our next option, the Skylake-based DAS testbed.

Yottamaster C5 in the GIGABYTE Z170X-UD5 TH ATX Motherboard

The installation of the Yottamaster C5 in the GIGABYTE Z170X-UD5 TH ATX board was uneventful - no drivers to install, as the ASMedia ASM3242 in the C5 uses Microsoft's XHCI drivers built into Windows 10 (May'20 update). As a first step, we took the SanDisk Extreme Portable SSD v2 (SuperSpeed USB 10Gbps) for which we already had recent benchmark numbers, and processed it with our test suite using the C5's Type-C port. The benchmarks with the ASM3242 host delivered better results than what was obtained with the Alpine Ridge port of our regular testbed - but this was to be expected, given the ASMedia chipsets at either end of the chain. After being satisfied with the shaping up of the updated testbed, we connected the SanDisk Extreme PRO Portable SSD v2 to the C5's port. Unfortunately, the drive kept connecting and disconnecting frequently (YouTube video link for screen capture). Sometimes, it stayed up for long enough to process a couple of iterations of one of the CrystalDiskMark workloads before disappearing (as shown in the screenshot below).

Initially, the suspicion was on the Plugable USBC-TKEY in the middle of the chain (kept in place for power measurement), but the behavior was the same with the direct connection too. The WD_BLACK P50 also exhibited the same problems. Based on the online reviews, this problem doesn't seem to be isolated to the Yottamaster C5 - ASM3242 cards from other vendors also appear to have similar issues.

Ruling out the Skylake-based testbed for the evaluation, we decided to attempt the installation of the card on our Haswell-based testbed. In this system, we no longer had the disconnection issue. Our test suite managed to run to completion on all the drives that we wanted to test.

Testing in Progress on the 'Best-Performing' USB 3.2 Gen 2x2 Testbed - (Core i7-4790 / Asus Z97-PRO Wi-Fi ac ATX / Corsair Air 540)

We did observe one hiccup in the set of tests - while processing the CrystalDiskMark 4K random reads and writes with 16 threads and a queue depth of 32, the system completely froze up for a good 30-60s before recovering (the effect can be seen in the CrystalDiskMark power consumption graphs in a later section). Our internal SSDs review editor, Billy, was able to reproduce the same with a Haswell-based system (using Core i7-4790K) at his end while using an Intel USB 3.0 port and a SuperSpeed 10Gbps enclosure using the JMicron JMS583 chipset. The problem was not reproducible with internal drives. Our inference is that the combination of high queue depth and thread count creates way too much driver overhead that the Haswell-based systems find difficult to handle.

As a final resort, we shifted back to the current DAS testbed, the Hades Canyon NUC. Taking the eGFX route, we connected the PowerColor Gaming Station to the Thunderbolt 3 port after removing its internal daughtercard responsible for all of its I/O ports. The PowerColor Gaming Station unofficially supports a SATA drive, which meant that its PSU has a spare SATA power cable. Using this, it was a breeze to get the Yottamaster C5 up and running in the eGPU enclosure.

Our test suite was processed on the WD_BLACK P50 and the SanDisk Extreme PRO Portable SSD v2 using multiple testbed configurations detailed above. We also processed the SanDisk Extreme Portable SSD v2 (SuperSpeed USB 10Gbps device) using the same ports for comparison purposes. The two SuperSpeed USB 20Gbps drives were also processed with our regular testbed to provide an idea of their performance when connected to regular Gen 2 (SuperSpeed USB 10Gbps) ports.

AnandTech DAS Testbed Configurations for USB 3.2 Gen 2x2 Testing
Configuration Suffix in Graphs Notes
Asus Z97-PRO Wi-Fi ac ATX
Core i7-4790
Corsair Vengeance Pro CMY32GX3M4A2133C11 DDR3-2133
32 GB (4x 8GB) @ 11-11-11-27
Seagate 600 Pro 400 GB
Yottamaster C5 USB 3.2 Gen 2x2 Expansion Card
Corsair AX760i 760 W
Corsair Air 540
[ASM3242] N/A
Intel NUC8i7HVK
Core i7-8809G
Crucial Technology Ballistix DDR4-2400 SODIMM
32GB (2x 16GB) @ 16-16-16-39
Intel Optane SSD 800p SSDPEK1W120GA
Intel SSD 545s SSDSCKKW512G8
PowerColor Gaming Station
Yottamaster C5 USB 3.2 Gen 2x2 Expansion Card
[ASM3242 via JHL6540] N/A
Intel NUC8i7HVK
Core i7-8809G
Crucial Technology Ballistix DDR4-2400 SODIMM
32GB (2x 16GB) @ 16-16-16-39
Intel Optane SSD 800p SSDPEK1W120GA
Intel SSD 545s SSDSCKKW512G8
[JHL6540] Alpine Ridge
Thunderbolt 3 port
used in
USB 3.1 Gen 2 mode
Core i5-6600K
G.Skill Ripjaws 4 F4-2133C15-8GRR DDR4-2133
32 GB ( 4x 8GB) @ 15-15-15-35
Samsung SM951 MZVPV256 NVMe 256 GB
Yottamaster C5 USB 3.2 Gen 2x2 Expansion Card
Cooler Master V750 750 W
Cooler Master HAF XB EVO
[ASM3242 Skylake] SanDisk
Extreme Portable SSD v2 only

The table above lists all the configurations that were tested, along with notes on the implications of the suffix seen in the graphs in the following sections.

Introduction Device Features and Characteristics
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  • six_tymes - Monday, October 5, 2020 - link

    spot on. thank you for posting truths.
  • vol.2 - Monday, October 5, 2020 - link

    When I read it, it sounded like the issue was with USB 3.X devices operating on a USB4.0 chipset. My assumption, and I don't think it was explicitly addressed, is that USB4.0 would be "full speed" per it's own specs. Of course, it wasn't explicitly addressed (from what I took away from this), so I phrased my comment as a question; "So wait for USB4 devices then?"
  • repoman27 - Monday, October 5, 2020 - link

    You’re reading is pretty much on the money, but the answer to your question is a bit trickier.

    The first USB4 hosts to hit the market will (probably) be Intel Tiger Lake based products which have integrated Thunderbolt 4 and support USB4 40Gbps. The USB4 spec requires backwards compatibility with USB 3.2, including both the Gen 1 (5Gbps) and Gen 2 (10Gbps) PHYs. It does not, however, require USB3 dual-lane operation (Gen 2x2, 20Gbps), and Intel has not included this optional feature in the controller integrated into Tiger Lake CPUs.

    If Intel doesn’t have any plans for integrated USB 3.2 20Gbps, I fail to see how it becomes widespread, unless Apple and AMD both embrace it in their future chipsets. On the other hand, USB 3.2 devices are probably always going to be cheaper than Thunderbolt or USB4 gear. Paying the premium for a USB 3.2 20Gbps device today is somewhat questionable, unless you have a capable host or the performance difference compared to other products when connected to a 10Gbps port is worth it to you.
  • magreen - Monday, October 5, 2020 - link

    Why will USB3.2 20Gbps devices always be cheaper than USB43 gear? It seems likely USB3.2 20 Gbps will be a niche product and without being produced in high volume, street price won't come down. USB4 might be initially expensive, but volume production and competition may bring street prices down to what we see today for USB3.2 Gen 1 5Gbps devices.
  • repoman27 - Monday, October 5, 2020 - link

    Because USB4 is essentially Thunderbolt, but even more complicated. It will always take way more silicon and way more power than USB3 on the same node. Thus it’s never going to be as cheap. Economies of scale can’t solve everything.
  • vol.2 - Thursday, October 8, 2020 - link

    Sounds about right. I don't have a sudden need for USB 3.2 dual lane. It seems like the best case for more parties to forgo support for it altogether and push USB 4.0. On a related note, USB 3.X has always been very buggy and unstable/unreliable for me, so hopefully 4.X fixes some of that.
  • Meteor2 - Monday, October 26, 2020 - link

    Not if you plug a USB4-20Gbps or a USB4-40Gbps SSD into them.
  • YB1064 - Tuesday, October 6, 2020 - link

    Why is the ASM2364 winning in every scenario compared to Thunderbolt, if TB offers higher bandwidth? Am I reading this incorrectly?

    WTF is this godawful nomenclature dumpster fire??? The idiots on the USB standards committee need to be flogged with extreme prejudice.
  • repoman27 - Tuesday, October 6, 2020 - link

    The ASMedia ASM2364 is the PCIe NVMe to USB3 20Gbps bridge chip used by the devices being tested for this review.

    The ASMedia ASM3242 is the USB3 20Gbps host controller that was used for testing these USB3 20Gbps drives.

    The Intel JHL6540 is a Thunderbolt controller which includes an integrated USB3 10Gbps host controller for interoperability with USB3 devices. This was used to test these USB3 drives while connected to a USB3 10Gbps host. The ASM3242 is winning because it supports twice the USB3 signaling rate as the JHL6540.

    When connected to a Thunderbolt 3 device, the JHL6540 supports up to 40 Gbit/s. In some of the tests, the ASM3242 card was actually plugged into a Thunderbolt 3 enclosure and connected to the host PC via the JHL6540.
  • Googer - Tuesday, October 6, 2020 - link

    It's kind of sad to think that USB is now faster than SATA. Will there ever be a SATA 4 for SSD and future bulk storage technologies?

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