I purchased a USB 3.0 Hub with external power supply. When attaching identical USB3 platter-based hard drives to the hub, CrystalDiskMark reports drive speeds of 80-90MB/s (sequential reads) for the drive plugged in to the first port. For the drive plugged in to the second port, CrystalDiskMark reports drive speeds of 36-39MB/s.

In all tests, only one drive was being accessed at a time.

Does this sound like the controller chip in the hub is poorly designed or would these be the expected results? If the results are expected, can you explain why?


UPDATE

According to USB Device Tree Viewer v3.1.7, the hub always adds a "USB 2.0 MTT Hub" with a PID of 0610, and a VID of 05E3.

About half the time, when I plug in the hub, it also adds a "USB 3.0 Hub" with PID 0612 and VID 05E3.

When attaching hard drives to the hub, they sometimes get enumerated under the "USB 2.0 MTT Hub", even when the "USB 3.0 Hub" is present.

Interestingly, according to Windows 7 (via USB Device Tree Viewer), the "USB 2.0 MTT Hub" uses the USB3 driver iusb3hub.sys. Why?

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    And the issue persists if you move the drive plugged into port 1 to 2 and vice versa? It's always port 2 that is slower, rather than a particular drive? – DrMoishe Pippik Jul 30 at 16:48
  • @DrMoishePippik That's correct. – RockPaperLizard Jul 30 at 17:48
  • What is USB VID and PID for the hub controller? It sounds like when both drives are connected, the hub falls into USB 2.0 mode... – Ale..chenski Jul 30 at 19:09
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    You need to check USB tree connectivity and resulting device speeds using USBTreeView, and report here. superuser.com/a/1181052/620011 – Ale..chenski Jul 30 at 19:12
  • Have you tested one drive plus another device -- say a keyboard in port 1 and a drive in port 2? – fixer1234 Jul 30 at 21:59
up vote 3 down vote accepted

USB 3.0 hub controllers with VID=05E3 and two PIDs 0610 and 0612 are manufactured by Taiwanese company Genesys Logic, according to Linux ID database. The chip controller is GL3520. This silicon chip is USB-IF certified, which means that it passes all requirements WHEN PROPERLY MOUNTED ON PROPER PCB with PROPER POWER SUPPLY and PROPER TRACE ROUTING. And this is the questionable part.

Here is a review of your hub product:

It says in part:

low-power devices like USB 3.0 card readers operate flawlessly off the hub – but devices which are a bit more power hungry like my SSD in a box fail to operate properly

I suspect that the power distribution along this "product" is not up to the task, and that's why the SuperSpeed links do not always work and are flaky, especially when two of HDD drives are connected and the link falls into USB 2.0 mode, with corresponding data transfer speeds. The hub product doesn't have USB-IF certification logo, probably for that very reason. You got what you paid for.

The fact that both hubs (2.0 and 3.0) operate under the same USB3 common driver is normal.

  • Thanks. Even plugging the hub in with no drives attached results in it sometimes just showing up in USB Device Tree Viewer as a USB 2.0 hub. Something must be amiss with it. – RockPaperLizard Aug 1 at 5:49
  • BTW, even though the PID and VID match, the hub reviewed is a little different. The hub I purchased has an external power supply and individual hardware switches for each port. – RockPaperLizard Aug 1 at 5:56
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    @RockPaperLizard, VID is vendor ID, and PID is Product ID, they are properties of hub controller IC. Functionality of a finished product however depends on workmanship and design of components around the IC, which is apparently bad in both cases. The other hub under review also has external power. – Ale..chenski Aug 1 at 15:22

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