USB randomly disconnecting and reconnecting

This will seem strange at first but it's backed up by my many many experiences building computers.

USB 3.0, in the way it communicates, has the propensity to develop RF interference in the 2.4GHz band. This will manifest itself in exactly the ways you describe above. Disconnects, wireless keyboard key press delays, etc etc.

As a simple test, enter the BIOS and if the ability to disable the MB's USB 3.0/3.1 ports is available, disable them temporarily and re-test. I'll bet your problems disappear or at least become negligible. Negligible, only because of possible other 2.4 band interference you may have there.

If disabling them helps all I can offer from experience is to get some 3-5' USB 2.0 extension cables, extend them as far away from the USB3.0/3.1 ports as possible, and plug your USB 2.0 devices to these. Thus separating by distance the USB2.0 and USB3.0/3.1.

It works here every time I build for a customer that demands a lot of USB devices be added. Extension cables stop this behavior dead in its tracks

Oh. Another BIOS option that may be available is Spread Spectrum Clocking, or likeness, that may give "some' relief.

This "modulates' the systems signals and is intended to reduce/negate the effects EMI/RF cause.

I had the same problem and the 970 Extreme3 V1 motherboard.
I used a shorter cable and the problem disappeared.
It's disappointing USB3 has this problem (if a cable is speced for USB3 then it should be shielded from interference).

shenmue wrote: Thank you very much for your answer. I plugged my USB 3.0 HDD further away from the used 2.0 port and the related issue has disappeared. I would never have thought about frequency radio.

Thank you for taking the time to reply that that helped. It's appreciated.

Hi :)