I have a 990 fxa UD 5 and I can't get the 1X pcie slot to function properly. It recognizes the card and it functions but the hashrate are way below and sporadic. I have tried the shorting method which did nothing except burn the Riser USB connection. So how do I get it to function properly and have the correct hashrate? The cards I'm using are the RX 470 MSI gaming X 4gb.
When you say that you "have tried the shorting method," do you mean shorting the A1-B17 pins on the slot?
What OS and drivers versions are you using?
What does the rest of your system look like? CPU/RAM/etc.?