After speaking with ASUS technical support, it turns out that I needed to go into BIOS

• Boot -> Enable 4G Decoding.
• PCH -> PCIe -> Gen2

This allowed me to use up to 5 riser cards. There are still 3 more slots on the board, but 5 is better than 3 so far.

Motherboard: ASUS Z270 Mark 2

from claymore-dual-miner.

Take Linux out of the equation. Take the riser out. Test the BIOS sees one of them. Swap the cards. Does BIOS see that one. Put riser in try all 4 combinations to determine if it is hardware or software

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The key is to trust nothing. Maybe the pci slot has some bad lanes. Maybe the riser you bought is bad, incompatible or you didn't give it power, or your power supply can't handle it. Also just try one card and put that in the riser. If it doesn't work in BIOS then you know it must be the riser

from claymore-dual-miner.

The BIOS seems a bit antiquated.

1 Card attached via a riser does work, but when I attach more than one riser it no longer works.

I am going to try getting a large power supply to see if that is the issue. The power supply actually doesn't have a power rating written on it.

The exact error message is:

cuda GetDeviceCount returned error 10
Invalid Device Ordinal
No NVIDIA CUDA GPUs detected
No AMD OPENCL or NVIDIA CUDA GPUs found, Exit

from claymore-dual-miner.

You are of course aware that you may need to short the 'presence' pins of PCI-e slots when using risers?

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from claymore-dual-miner.

That depends on the riser. I didn't have to do anything with mine. But they are powered risers. Everything I read has said to use powered risers and you won't have problems.

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http://blog.zorinaq.com/whitepixel-breaks-286-billion-passwordsec/

Search for : Shorting Pins for "Presence Detection"

I also disagree with the comment above, in case it was stating that powered risers allow you to get away without shorting presence detection. This was definetly false in the tests I've done

from claymore-dual-miner.

@nueverest I tried your setting, but still cannot detect the GPU connected with riser, other 3 GPU directly plugged in the motherboard are detected.

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