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


View All Comments

  • epobirs - Wednesday, October 7, 2020 - link

    This was tried and rejected by the world already, under the name SATA Express. A whole generation of motherboards shipped with SATA Express ports but nobody made any drives of any sort to use with the port. (IIRC, WD had a demo at Computex one year.) The closest I ever came to using a SATA Express port for anything was the clever ASrock adapter that let you repurpose the port to create a pair of USB 3.1 ports, Type A and C with 10Gb/s support, that went into a front drive bay.

    Once NVMe caught on it just didn't make much sense to pursue a direct successor to SATA.
  • Hrunga_Zmuda - Tuesday, October 13, 2020 - link

    Exactly. Reply
  • StormyParis - Monday, October 5, 2020 - link

    Performance is one thing, and I understand it's the primary concern in some cases.
    In most cases though, compatibility not performance is the main issue, and we run into 2 problems:
    1- it's hard to know what *should* work. A USB-C port doesn't mean anything at all by itself, there's not even a color code as a quick hint. Any consumer tech that requires to RTFM is failing at a very basic level.
    2- even stuff that should work sometimes doesn't. Apparently USB-PD charging on MacBooks works much better on one side than on the other. I've seen a lot of issues with video, even simple storage/LAN stuff.
    The goal of USB is laudable. The way they're going at it is laughable.
  • drexnx - Monday, October 5, 2020 - link

    yeah, USB used to mean it just worked, didn't have to think about it or read anything. Literally plug and play.

    now? no clue, unless the mfg puts iconography to let you know what each port can do.
  • imaheadcase - Monday, October 5, 2020 - link

    Even with speeds it varies so wildly by device its silly. The real only advantage i found with a SSD for portable drive is the size and weight is better. Performance is Meh, because most people aren't using it for own devices so much as plugging it into someone elses. I've seen top selling drives that will barely get usb 2.0, and even then the read/write to usb speed is insanely different between devices. Reply
  • imaheadcase - Monday, October 5, 2020 - link

    I forgot to mention that even cables mater so much, i'm not talking about scam monster cable stuff, i'm talking just even same brand to brand, can get a bulk 20 pack of usb-c cables, and each one could be different in speed. Reply
  • BeethovensCat - Monday, October 5, 2020 - link

    Agree!! A complete joke! Have Patriot and a Sandisk SSD and they don't work with the same USB C cable. How can USB have come to this? Reply
  • drexnx - Monday, October 5, 2020 - link

    this is really getting back to the dark ages of RS232 where there were different baud rates for different peripherals, now that I think about it Reply
  • dontlistentome - Monday, October 5, 2020 - link

    I'll bite. Bit of a correction on diagram, more complexity needed.
    USB 1.0 was 1.5Mbps, USB 1.1 was 12Mbps
  • repoman27 - Monday, October 5, 2020 - link

    Nope. USB 1.0 defined both low-speed 1.5 Mbit/s and full-speed 12 Mbit/s signaling. It just sucked, which is why 1.1 was released to fix a bunch of issues that were encountered in real-world implementations. Reply

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