Newest Gigabyte BIOS boards (I had F10 and upgraded to F11 on Gigabyte Z390 Aorus Master) do not allow you to disable "Super IO Serial"
This thread here has more information about disabling it now.
This thread relates to a crash that may occur in Mac OS X El Capitan 10.11.x or earlier with some motherboards that have a serial port. This is no longer an issue with macOS Sierra 10.12.x. I have my serial port working in Mac OS X, and I am posting here my experience with that. Many guides...www.tonymacx86.com
Please. Head up to the Idiots Guide to USB ports in General Help.
You are running issues with your USB ports.