I had hoped it was the Gigabyte model: 990FXA-UD3, that one is known to need "iommu=soft" to get USB to work.
I have this Gigabyte board and need to start live mode (UEFI) by hitting 'e' on the boot menu, then hit 'end', space, then typing iommu=soft
Give that a try, see if that fixes it for you too, if so, you can make that permanent after the install by adding it to /boot/loader/entries/kaos....conf