Sorry for the late response ... moved on to issues with AMD cards :-)

Here is my reply from another post.  Let me know if you need further details:

---

Try this ... it worked for me to get all 6 cards working:

Reset the BIOS by removing the battery
Update the BIOS if you have not already (you can do this before or after the resetting)
Boot the os with 0 GPUs connected and change your BIOS settings to mining mode and use the onboard VGA (IGFX)
1 by 1 install the GPUs rebooting in between ... not sure this is necessary, but it worked for me

THis worked for me in SMOS (or linux), so I hope it works for you as well.  Basically what was happening is that there was a collision at the kernel level with this mobo trying to output video from card 1 and the IGFX because you may have booted the machine with a GPU installed int he 16x card slot.  At least that's what the system messages in the LInux OS told me.

Good luck mining ... especially after the ETH difficulty increase :-(

---

Try this ... it worked for me to get all 6 cards working:

Reset the BIOS by removing the battery
Update the BIOS if you have not already (you can do this before or after the resetting)
Boot the os with 0 GPUs connected and change your BIOS settings to mining mode and use the onboard VGA (IGFX)
1 by 1 install the GPUs rebooting in between ... not sure this is necessary, but it worked for me

THis worked for me in SMOS (or linux), so I hope it works for you as well.  Basically what was happening is that there was a collision at the kernel level with this mobo trying to output video from card 1 and the IGFX because you may have booted the machine with a GPU installed int he 16x card slot.  At least that's what the system messages in the LInux OS told me.

Good luck mining ... especially after the ETH difficulty increase :-(

OK.  So I'm an idiot or just rely on others' help a little too much.

Here's the issue, when I first booted the board it defaulted to use the GPU #1.  I did not plug in the other GPUs to test it out.  That made the mobo configure itself to not use the built in VGA out lanes.  I found this out by checking the DMESGs and logging in myself from an SSH connection to SMOS.

Well after full CMOS restart I'm getting all the GPUs to be detected and hashing.  I have already started seeing some good ETH income.

Thanks all of your help!

Thanks.  I ordered another set of risers.  I tried swapping this riser already and put it in a working, slot and it works in another slot.  Do you think it could be that another another riser could be causing the 6 risers to run altogether?

Yes.  I have a SATA cable powering the riser and a direct VGA 6 pin to the GPU.  Also all fans spin during bootup, but only 5 are detected when the OS comes around (SMOS).  Also I have 2 molexes going into the motherboard for additional PCIE powering.  I have also tried directly powering the riser with a 6 pin vga power cable.
 I see that at max I am only using around 580W.  

Do you think it could be the OS not detecting 1?  Would it be worth my trying to plug 1 card in directly to the motherboard?

I tried swapping that riser, and it works in a different port.  In fact I've tried swapping all the riser components and gpu itself and everything works in other slots.  Thanks for the suggestion though.

Thanks guys so much for your help ... and Happy New Year.

So I tried Gen1, Gen2, Gen3, and then Auto and nothing.

I also tried the instructions mentioned in the mining manual.  After enabling everything the rig won't boot and the VGA onboard chip is giving me a multicolored random pixels screen (i.e. a lot of garbage).

Do you think it could be because I am running SMOS from a USB thumb drive?  Is there any other OS I should try?

Bumping this thread, as I am having the same issue with 5/6 GPUs detected.  I have tried everything in the thread and still no luck.  Could it be the OS?  I am using the vanilla install of Simple Mining OS.

Hi All,

This is my first post to the bitcoin forum, and I'm hoping someone can help me.  I'm at the end of my rope   So as to my issue, I have this Gigabyte GA-H110-D3A motherboard with 6 Nvidia 1060 3GBs and for the life of me I can't get the 6th card working in SMOS.  I have tried many things and nothing has worked:

• Update the BIOS to the latest and trial and error all BIOS settings, such as Legacy PCI, Mining Mode, 4G Decoding On & Off
• Increasing the PSU to 1000W Titanium and I have verified that the power never goes about 600W
• Plugging in the molexes to power the PCIe extension slots
• Tried using an M2 to PCIe adapter.
• Swapped out all hardware to confirm that the riser and GPU are functioning correctly.  In fact if I use the 6th riser without the 5th (or any other) SMOS detects the 6th card, but I am still stuck at 5 GPUs

Please help as I am at my wit's end and need the help of my fellow miners.

My congfiguration:

• Simple Mining OS
• Gigabyte GA-DH110-D3A Motherboard
• EVGA 850 Watt Platinum PSU
• Intel Pentium G4400
• Ballistix 2400 DDR4 RAM
• 6 GPU Risers
• EVGA NVidia 1060 3GB SC (single fan)