I have about a dozen USB 3.0 devices per machine at my office (external hard drives) on both Windows 10 and Ubuntu. I have noticed that when you get to this scale, USB 3.0 starts being less reliable and devices, ports, or hubs may randomly disconnect. Sometimes this is caused by sudden power draw (such as plugging in a portable HDD without an external power adapter), but sometimes it seems some devices or ports are just wired incorrectly. For example, there is one USB port on my machine where anything being plugged into it causes the other devices to momentarily disconnect.

How can I test that ports and devices are meeting the USB 3.0 spec?


You need a device to measure USB device current draw. Such a device is an adapter that fits between the device and USB port. That is because you normally need to break the circuit to measure current.

It is a reasonable assumption that the basic port is fine (you said as much), so current draw of numerous devices is likely the issue.

You need to measure one device at a time, document the reading (the Klein tool can store 10 readings), but I would still document and then move to the next device.

Here is such a device:

Klein USB current meter

3 to 20V DC; Current: 0.05 to 3A

Continuously monitor up to 1000 hours of voltage, current, capacity/charge delivered, energy, and resistance (calculated)

Tests most common standard USB-A ports, including Qualcomm Quick Charge® ports

Store and recall up to 10 readings

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