I have this type of motherboard with 13 GPU running under Linux but I must have a faulty motherboard because some slot are not giving the best performance. If I swap cards or risers, it doesn't change anything, some slots are not performing very well. If I take a card and riser that is performing well on one slot and move it to a slow performing slot, my hash rate goes down while it was higher with the same card + riser on another slot.
I also have one of my slot that makes the whole rig unstable for some reason. If I use that slot, the rig crashes after a couple of hours while when I'm not using it I can mine a week without a crash.
I contacted Asrock and they suggest to return the motherboard. Have any of you had a similar experience?
I suspect that I am having a similar issue with my x16 slot. if ANYTHING gets plugged into that slot, the rig will not get past the black screen. Ironically, I am setting up a second rig with another H110 Pro BTC+ and it has the EXACT same issue -- anything plugged into the x16 slot causes black screen on boot. I haven't contacted ASRock yet, but returning the board could be a dubious proposition since they are not currently in stock anywhere......