I’m currently running a rig with a msi z390 a pro successfully with 11 gpus
The pci slot mapping are :
1: PCIx16 → splitter 1 to 4 : 4 gpus (4xriser)
2: PCHx1 → 1 gpu (riser)
3: PCHx1 → 1 gpu (riser)
4: PCHx4 → splitter 1 to 4 : 4 gpus (4xriser)
5: PCHx1 → 1 gpu (riser)
6: PCHx1 → empty
My bios is set up and i disabled audio + serial + parallel, video set to IGD and screen on motherboard DVI port.
Unfortunately when i plug my card #12 it does not work (i’m not even seeing the bios … i got a black screen)
Did some have managed to make it work with more than 11 gpus and how ? I believe I ran out of pci lanes (This topic is hard to fully understand and gave me headache about pci / pch , cpu and chipset max lanes , why the 1 to 4 spliter has a x1 form factor -will sound logical it have x4 form factor as it split x4 to four x1 lanes …).
Anyway if we have some expert on the topic I would like to know if trying to disable usb in the bios could free some pci lanes (this means I should buy a ps2 keyboard and migrate my hiveos usb dongle to a sata ssd) ? other option is to disable sata but it seems not possible on this motherboard (no option in bios) … btw i was unable to find a block diagram to know if my m2 x4 port (currently unused) is PCI or PCH -this could be a third option to add gpus-
Thanks for any advise on that