Issues after installing 5th graphics card

I've managed to run 4 graphic cards so far with this setup.

  • Motherboard: Asus Prime Z270-p
  • 4 x GTX 1060 3G (ultimately need to install 6)
  • RAM: 8 GB
  • Intel pentium 1151
  • Cards are connected via powered risers

Relevant software – Ubunutu 17.04 – Latest Nvidia binary driver 281

I know that installing 4+ cards is usually problematic in Linux. I've been following the instructions in and they helped me install 4th card. However, the instructions are extremely indeterministic and don't have a clear order. They usually involve:

  • Turn on/off Bios "Above 4G decoding".
  • Change PCIE link speed to Gen 1, 2 or 3.
  • Change DMI Max Link Speed to Gen1, 2, or 3.
  • Add one card at a time.

Once I install 5th card into motherboard and turn on computer, I get one of the following issues:

  • Ubuntu boots fine but "nvidia-settings" only shows 4 cards
  • BIOS splash appears but black screen afterwards.
  • No output signal at all.
  • No BIOS splash appears. I just get the error:

Error: unknown filesystem. grub rescue>

Random questions I have:

  • Does it matter which card has HDMI plugged? Should I rely on the integrated intel gpu instead?
  • When people say "install one card at a time, then install drivers", aren't drivers already installed?
  • There are 6 PCI-E slots 1) PCI-E x16 (x16 mode), PCI-E x16 (max x4 mode) and 4*PCI-E x1. Do they differ in anyway? Is there supposed to be an inherently primary slot?

I realize I'm completely lost and can't make sense of what I'm seeing. But that's why I'm here! I'd really appreciate any debugging tips.

Thank you

Submitted June 19, 2017 at 02:05AM by rgeorgy
via reddit