Can’t get 4th GPU to show up (M.2 to PCIe)

[DaNoobz]

Hi,
I have an ASUS TUF GAMING B450M-PRO S Micro ATX that I can’t get 4 GPUs to work on. I wouldn’t have chosen this mobo for mining but was part of a Newegg shuffle win. 3 GPUs work perfectly but I was hoping to leverage the two M.2 slots to add 2 more GPUs (rig has a 1300W PSU). I am using a M.2 to PCIE 1x adapter. When I connect 4th GPU to M.2 slot closest to CPU, it doesn’t show up and BIOS says no NVME device detected. I moved the adapter to M.2 slot in between PCIE 16x slots and the new card showed up but it replaced the card in the second PCIE 16x slot. BIOS allows me to choose M.2 or PCIE (Auto mode defaults to M.2 device if detected), so I changed it to PCIE, and I can see the 3 original cards but not the new card connected via M.2 adapter. Is there a way to make this work?

Thanks in advance!

Mobo expansions slots specs:

CPU is Athlon 3000G

[Batfink]

Athlon 3000G has 6x PCI lanes, Integrated Vega graphics uses 2 lanes only leaving 4 lanes for external GPUs.

If your mobo has onboard LAN then that might be taking up one of the available PCIE lanes. Try disabling the onboard LAN and see if the 4th GPU works. Also disable everything on the mobo you dont need (sound, SATA ports, serial ports, parallel ports, etc) something may be snatching that last PCIE lane on bootup before the 4th GPU can initialise.

Athlon 3000G - AMD - WikiChip