I have the same board too. I use Linux and all of my 7 cards get recognized instantly without any pin to be shorted. I only need to change the 3. PCIE16 slot in BIOS to gen2 to recognize the 7. card.
But problem comes when I started ccminer. The machine crashes instantly and restart. I have look at all the logs but found nothing. It seems like the board won't deliver enough power for all 7 cards. Of course I use power risers on all cards.
It is very strange but I still don't have time to test more. Im staying with the 6 cards setup with Asrock H81 BTC pro now.
ur welcome, i also forgot to mention the gen settings in bios. I set all of mine to gen1. it just seemed the easiest thing to do, remove the need for extensive troubleshooting just to get them working properly
that's interesting, what u shared about ur linux setup.
wish i could help u with the problem u describe about 7th card crashing ur rig, but tbh, i believe i got lucky with my rig. sure, i had a tough time getting all 7 gpus recognized in bios, but once i did, it runs quite smoothly.
incidentally, my psu is 750w. and my 750ti gpus are zotac twin fans. all 7 have 6pin pcie power. I thought of mentioning since u suspect ur psu is not supplying enough power. u may be right, only way to test for sure is use another psu, bnew or higher wattage.
last item for ur reference: my 7gpu rig, g3220, 16gb ram, ssd, bronze 750w psu: uses 365-390w x11 (reading takeng from power meter)