Strange issue with Asrock H81 Pro BTC R2.0 motherboard

[zoufou]

After having 2 mobos working well with 6 GPUs each, i decided to buy 3 more of the same model (Asrock H81 Pro BTC R2.0) and got stuck being able to run only 5 GPUs per mobo, i've tried many tricks including using PCI-E card instead of the onboard, disabled audio, serial devices and anything else, changing risers, usb cables, power cables, dedicated psu for GPUs ... etc

I'm always having the last PCI-E port not working (the one on the edge of the mobo).

Did anyone of you get the same issue ?

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[Geraldo]

What card type are you using? Are the troubled mobos using the same kind of card with the other two mobos that have run well? Is your PSU enough for six card?

I'm always having the last PCI-E port not working (the one on the edge of the mobo).
Is it only by installing one card, that troubled socket can work well?

Try to reset bios on your mobos. (do again) Check all cable, riser and another part that may be causing those problems. Only general advice that we can give to you for now except you describe more details about all devices that you are using.

[stash2coin]

Are you using the M2 slot? When using the M2 slot not all PCIE slots will work.

[Geraldo]

Are you using the M2 slot? When using the M2 slot not all PCIE slots will work.

Those board didn't have an M2 slot.

[Lampaster]

Maybe the problem is that you do not have a slot? Any equipment may contain defects. I have 3 rigs work on such motherboards. I don't have any problems. Everything works reliably. The fact that you bought 2 of the motherboard does not reduce the probability of defects. Perhaps the entire batch of equipment was defective.

[smoolae]

I had the same problem with the same MOBO but with 5 cards. Tried all the different things but only could get 4 showing (thought already that the 5th card had died )

Then tried DDU and chose this "Install new GPU" option (5th card was plugged in throughout the whole process). It worked and my 5th GPU magically appeared .

Maybe this will work for you too!

[Geraldo]

You may need to try this advice.

Then tried DDU and chose this "Install new GPU" option (5th card was plugged in throughout the whole process). It worked and my 5th GPU magically appeared .

[zoufou]

I had the same problem with the same MOBO but with 5 cards. Tried all the different things but only could get 4 showing (thought already that the 5th card had died )

Then tried DDU and chose this "Install new GPU" option (5th card was plugged in throughout the whole process). It worked and my 5th GPU magically appeared .

Maybe this will work for you too!

What is DDU ? is it a windows thingy ? am all on linux ...

[Geraldo]

What is DDU ?
DDU refer to Display Driver Uninstaller.

is it a windows thingy ? am all on linux ...
That's why you need to describe more detail. 

[fanatic26]

in linux, does the OS see all of the cards?

e.g.

[/root]:# lspci |grep VGA
01:00.0 VGA compatible controller: NVIDIA Corporation GP104 [GeForce GTX 1070] (rev a1)
02:00.0 VGA compatible controller: NVIDIA Corporation GP104 [GeForce GTX 1070] (rev a1)
03:00.0 VGA compatible controller: NVIDIA Corporation GP104 [GeForce GTX 1070] (rev a1)
04:00.0 VGA compatible controller: NVIDIA Corporation GP104 [GeForce GTX 1070] (rev a1)
06:00.0 VGA compatible controller: NVIDIA Corporation GP104 [GeForce GTX 1070] (rev a1)
07:00.0 VGA compatible controller: NVIDIA Corporation GP104 [GeForce GTX 1070] (rev a1)