Hi,
I have a problem if I try to connect more than 6 GPUs to my AsRock H81 Pro BTC v2.0 mobo. I bought an extender riser (PCI-E x1 -> 3*PCI-E x1) and I use normal USB3 PCI-E x1->x16 risers. Everything's fine until I connect the 7th card. I can connect the first 6 card any way I want it but after the 7th card connected I got blank screen when I turn on the rig.
How do I make it work with 7 or 8 cards?
are you using Windows 7 perhaps? I have an 8 Card system and the only way I got them to work was with Windows 10 and Ubuntu. But it can also be the fact that your MB don't support more than 6 PCIE cards. Have you tried connecting 5 cards and one dual card? such as 7990, 295x ? I have two 7990 and 4 other cards in my 8 card system. Not using the PCI Switch.