I'm experiencing the same issue on 2 different machines that have been running fine for close to a year... until about 2 weeks ago. I believe that it's a Windows 10 issue. For some reason Windows forced security updates even though I had them turned off. One machine will allow me to run 4 cards but not 5/6. I isolated different cards on different risers and it hangs no matter which 5 are operational so I know it's not riser/card. I uninstalled/reinstalled driver, reinstalled windows, reinstalled driver.. nothing. Has anyone come across this issue and been able to get their machine working?

I'm running RX 580s on Windows 10.