ASUS Prime Z390-P -- Can't install more than 4 GPU, though it has spots for 6

https://www.asus.com/us/Motherboards-Components/Motherboards/All-series/PRIME-Z390-P/techspec/

Any idea what I need to do to add the 2 extra GPUs? I researched something about bios changes, but I wasn’t successful.

This server should help :slight_smile: https://discord.gg/bMmJUTcaBT

If you have NVME SSDs in any of the NVME slots, it’s likely that the 1x slots will be disabled.

Are you using NVME SSDs?

If you remove them, you should be able to use the 1x slots.

I am not using any ssd, thumb drive running hive os.

So then, what happens when you install all 6 video cards??

The GPUs are not recognized. They are fully installed, have power, led lights on, but they won’t mine. It is like perhaps the motherboard cannot recognize them. I have tried some recommended bios settings PCIe - gen2, turn off on board GPU, etc.

What kind of risers are you using? “USB style” or “Ribbon cable”?

Are your risers the kind that only supply 12V and require 5V input separately for the GPU to initialize?

Can you take a picture of one of your risers and share it here?

I found the culprit. It was the GPU risers. I must have gotten a bad batch, but literally, 3 out of 16 were functional out of a recent amazon purchase. Simple, bought new ones and it worked perfectly.

Thanks everyone for the advice.

I have the same MB, same problem. Can’t get to recognize the 4th card. I, too, have new risers, but they’re from Mining Cave. I guess I’ll start switching them out to see if that’s my problem. Thanks for the update!

Oh man, that sucks!

Glad to hear you at least found the problem.

I was googleing this is a known issue it seems. the max i can get working is 5 only when i have 6 plugged in. but then somehow i cannot boot into the bios after doing all the 4g enable and pcie to gen 2. I am running a ssd on the m key but not nvme so i am not using a pcie bus but a sata port.

using risers from gpurisers.com i have mixed and match cards to risers and ect. at this point gonn have to reach out to asus. unless someone got them working here.

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Let me know if you made any headway…

FYI…did you try a standard pcie riser vs. the usual gen 2?

I came a cross a site and used some of the settings.
https://forum.getpimp.org/topic/9/setting-up-motherboards-for-mining
Updated the bios to PRIME Z390-P BIOS 2820
Fastboot disabled
4G encode enabled
HD Audio disabled
Serial Port disabled

I left onboard Graphics because all my gpus are p106-100 with no video out. And left the pcie to auto. seeing that should not be the cause. And it works. i was able to get all 6 working. I am hoping to add a pcie 1 to 4 splitter/expander when i can find more cards. baby steps before getting new stuff again.

as for your riser question. again i left it to auto. I think doing the force caused my issue. and gpurisers.com did not ask for custom settings.

Having the same issue. I have 5 rx 580 gpus, prime z390-p motherboard and only 4 of them are able to mine, the 5th one has a red x. I’ve tried rearranging them, all the GPUs and risers are fine, it just has trouble when i hook up a 5th gpu. I have updated the bios and changed the settings to no avail. Any ideas?

Figured it out! I disabled all sata ports, disabled onboard lan, disabled audio, disabled memory remap, enabled 4g decoding, and using pcie gen1. All 5 gpus are now working.

same issue.
on Z390-P I was able to get 6 GPU working after 4G enable
but on Z390-A, I am not able to get 5th GPU working no matter what.
Tried every setting; PC does not boot… just blank screen.
As soon I take out one PCI-E slot, it works.

not sure about the A. but what i did was i plugged each card one at a time to one pci slot without risers to make sure all the cards work see pictures bad card has no serial. then repeat same thing 1 riser plugged in and cycle the cards. once all cards tested then add each new riser and card. I had a faulty card in one of my rigs and a bad riser in another. The site i included has options for intel boards then for 390 chipset and for Asus boards. My friend needed to use the 16x16 riser to get 6 working on one of his boards. its all trial and error. Hope this helps.