I have the same issues as the description above. Exact same rig with the right BIOS settings. The cards are not detected on the boot. The Q270 has a screen where you can check if the cards are recognized or not. If they are, the gpu slots are becoming green, if not, they are orange or red. In this case, you sometimes see GPU slot 1 green, then you press reset and you see gpu slot 2, 3, 4 on green, the gpu slot 1 (which was green before) becomes orange/red.
Could the PSU not be sufficient? Anyone idea?
Thank you so much for reading this, and have a pleasant day.
Done that as well. I get only 5 cards working, without any issues. Sometimes I get 7 cards (green), but then I receive an error from HiveOS that the cpu is stuck, and then I have to reboot and do it all again. With 5 cards it all works fine.