This is my 1st build and I'm using the AMD 7850k APU along with this board. All of the usb3's worked at first,then quit. During the process of later installing an R7-250 graphics card, they worked for a short time,but then quit again. My device manager shows 3 unknown devices and when I click on their properties and go into details, the 1st one is ultimately identified as "AMD usb 3.0 host controller,so I'm assuming my problem lies within this controller. I'm pretty sure I have everything set up right in the BIOS w/everything being updated.When I google the vendor and device info, I get led on the 'ol goose chase. Can anyone offer a solution.