First time I was able to install Sierra it was with SierraAMDv3 (10.12.4), after a lot of bumps it worked.... not completely.
I've had always USB problems, my web cam didn't work, crashed my system, the external HDD sometimes I had to connect it to nearly all USB ports 2.0 and 3.0 for work, USB drives happened the same.... but I knew it wasn't right.
Then 2-3 days ago I was reading a Success Storie from our beloved AMD OSX forum with "My Long Battle with USB" for title and it seemed what I was looking for.
Today I've tried it and worked.... not the way Sjguk succeeded, but it worked.
I didn't have to remove AppleHidMouse.kext, but systems are different, they may have other needs.
Since in Success Stories it can pass disguised and here is easier to be noticed. Follow the link to the original Sjguk post viewtopic.php?f=35&t=1746
NVIDIA GTX 980
AMD FX 8350