I'm facing a problem with this motherboard trying to make it work with 6 pcie GPU's for eth mining.

Current setup:

  • Asus Rog Strix b450-f AMD Ryzen Pro 3 3200GE Pro (w/ radeon vega 8)
  • 4gb ram
  • 6 x Asrock Challenger Pro AMD Radeon 5700 XT 8gb

I'm currently using RaveOS (raveos.com) as OS to mine with ethminer.

I was able to make it work with 5 GPU, using slots PCIEx16_1 and PCIex16_3 and PciEx1_1, PciEx1_2 and PciEx1_3, the problem comes with slot PCIex16_2, I found no way to make it work.

Tried several bios setup combinations with no luck. OS is not able to found any GPU on slot pciex16_2.

Note 1: I'm using risers on 6 GPU.

Note 2: Tested every GPU + riser alone and they are working, so I guess all parts are working correctly.

Does anybody has any experience with this?

Thanks in advance


Following Bob answer, I found this on the motherboard manual:

Asus Rog Strix b450-f Manual (Snapshot)

So, Ryzen 3200 + Vega does not appear to support PCIex16_2 lane... I have to confirm this and mark appropiate answer.


Your cpu only has a limited number of pci-e lanes available. Sadly I can't find the official documentation but from different forums and other people with these issues it appears that the 3xxx series apu does not support a second PCIex16 slot.

  • Hi Bob, thanks for your answer. I've read something about that, but not too much info. So, the problem is with the Ryzen 3xxx + Vega 8 ? maybe I need one without inc. video? If you found any more info about it, I'll appreciate it! Thanks.
    – webbi
    May 11 '21 at 12:43
  • Just to be sure... I'm able to use PCIex16_1, PCIex16_3, PCIex1_1, PCIex1_2 and PCIex1_3 but not PCIex16_2? is that right?
    – webbi
    May 11 '21 at 12:46
  • 1
    From what I can see. you are correct. the 3xxx series without gpu is actually zen2 the apu's are zen+ where lanes are reserved for the igpu. The reason why PCIex16_2 isn't available is because it usually leeches of the PCIex16__1 slot. In this case the lanes it uses are rerouted to the igpu in the 3200 you're using. as stated in the manual you found, the reason the PCIex16_3 slot works is due to chipset PCI-e lanes.
    – skippy
    May 11 '21 at 14:13
  • Bob, thanks again for your detail. What you think about using a nvme port with an adapter to pciex1?
    – webbi
    May 11 '21 at 16:32
  • 1
    Sadly I have no experience with using those adapters but from the manual parts you've sent it might work. depending on the m.2 slot you use. Be sure to check though, sometimes using an m.2 slot either disables other pci lanes, or, if those lanes are in use, they run in sata mode, so wouldn't support a gpu.
    – skippy
    May 12 '21 at 9:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.