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?
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