How to run 6 gpus on ASUS 390-P

I have a ASUS 390-P with 6 RX 580 XTFs currently all plugged in and powered, but when I run Hive OS it only detects 5 cards. I have tried updating the bios and changing to gen 1 pcie, but nothing is working. Also its not a problem with the riser or card because i can interchange them with no issue.

Kyle having similar issues with the same board but different cards. For mine though I am trying to get five 5600 XTs running, but it will only recognize four of them. Let me know if you find a solution I will do the same.

After playing around with the bios, I am now able to detect 6 RX 580s, but now one of them does not work. The fans stop spinning and it just idles. If someone can help me out with this it would be great.

What did you change in the bios?

I enables 4g encoding and changed all the pcie speeds to gen 1. And after that i got 6 cards detected but only running 4

Kyle, I got all mine working by enabling Above 4G encoding as well. My PCIE settings are set to gen 3. But also my cards are PCIE 4.0.