GPU1 Disabled in nVidia Settings - Ubuntu 18.04.4

My Hardware:

  • Asus z170-K Motherboard wit 2 PCIeX16 Slots (0 &1)
  • 2 identical PNY nVidia GeForce GT710 GPU Cards (w/ 2 monitors connected to each via HDMI and DVI)

What I’ve done:

  • Installed Ubuntu Desktop 18.04.4
  • Configured Repositories (enabled Universe, Multiverse, Canonical Partners and bionic-proposed)
  • Ran system Upgrade (apt-upgrade)
  • Rebooted.

Note: Up to this point - all 4 connected Monitors work fine.

After Reboot:

  • Installed nVidia proprietary driver (ubuntu-drivers autoinstall) - Version 440.59 installed.
  • Rebooted.

Note: from this point on, only the 2 Monitors connected to the first GPU (GPU0) work, the others stay in STDBY mode.

After 2nd Reboot:

  • Launched nvidia-settings.
  • Both GPUs appear, but the Monitors connected to GPU1 are disabled.
  • When I try to enable them, I am forced to configure a new Xorg Screen for them.
  • When I do, after another reboot, the Monitors connected to GPU1 turn on, but show only a blank black background and the only think I can see on them is an X Server “X” mouse pointer…

Please help me figure this out!

That’s a configuration not really well supported using the proprietary driver. In the beginning, you were using the nouveau driver so all monitors worked.
Using the proprietary driver, you’re left to enable Xinerama to get all 4 displays working as a combined workspace. Xinerama has limitation and downsides. The nvidia counterpart ‘Mosaic’ is limited to Quadro type cards.

I have a similar problem on Ubuntu Desktop 18.04.4. I had been using a pair of EVGA 560 Ti’s on the 390 proprietary driver. I was able to run all 4 monitors across both cards. I upgraded to a pair of Asus RTX 2060’s and with that the requisite upgrade to the 440 series of driver. At that point, I was only able to get the monitors on the first GPU to activate. Is there some legitimate reason that the “Mosaic” feature was removed? I did verify that both my GPU’s work in windows as expected with the same mosaic-like behavior. Is there a chance the removal of this functionality was unintentional and it will be returned?

I can still return these video cards, so having a little guidance on if this feature will be returned would be helpful.

There’s simply no sense in doing that, just connect all four monitors to one card. GPU performance doesn’t add up (except for cuda).

Or monitors that do not have HDMI inputs. Regardless, I made everything work with a single card, and returned the second. Moving on. Thanks.