No device works in the USB3.1 ports at all. USB3.0 thumbdrives, USB 3.0 hub, Oculus devices. Nothing. At the BIOS level, if I have a USB3.0 thumbdrive connected when I power the machine on, the BIOS does not show that device as connected, so it's not an OS issue. There is power to the ports as my bus powered hub has power, but nothing connected to the 3.1 ports is recognized.
My build is nothing special.
Ryzen 1800x
Radeon RX480
Syba PCIe 2.0 X4 RAID card with two mSATA SSD's RAID0 (Will probably switch to a M.2 1TB SSD down the road)
Inateck PCIe USB 3.0 card
32GB Crucial RAM (Two BLS16G4D240FSB sticks)
PC Power & Cooling Silencer MkII 950W PS
In Windows, when not working, the AsMedia controller does not show up, and as I said earlier, the driver setup fails because it can't find the controller.
It does seem like there may be something flaky in the BIOS, because one thing I've noticed is when I make changes and 'save and exit', sometimes it powers the machine off and then powers it back on a second or three later, and sometimes it doesn't - even changing the same thing (for example, disable the USB3.1 controller and exit, then next boot enable it and exit. Sometimes it powers off both times, sometimes only one of them, sometimes neither).