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.
I use Win10, but I can't get to boot the OS. I turn on the rig and nothing happens. I don't have dual cards, I use RX470 GPUs.
Maybe AsRock H81 Pro BTC v2.0 mobo doesn't support more than 6 PCI-E devices? I tried to disable integrated audio, serial ports, etc. in the bios, then connected the 7th card but also didn't work.
I don't want to buy an expensive server/workstation mobo. Is there any chance to use 7 or 8 PCI-E devices? I searched for modded bios for this mobo but didn't find anything. Or it's the limit of the H81 chipset, not the bios?
It is my understanding that each GPU requires a minimum of 1 PCIE lane/pipeline to transmit data. That means you would have to plug the 1x3 card into a slot with at least 3 lanes/pipelines (in the real world that means a 4x, 8x, or 16x slot). The H81 Pro BTC has a single 16x slot and five 1x slots. You could only ever run the 1x3 card on the 16x slot.
If I'm wrong on this I am open to correction. I've actually been wanting to play around with the exact setup you describe.