An Unholy GPU Alliance Under Linux

Software & Operating Systems Linux
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I am currently planning a Linux System with a nVidia 1080Ti from Asus powering an Alienware 34 in 4K G-Sync Display on Displayport 1.4 combined with a Vega 64, also from Asus, powering two 24.5 in 1080P display’s on HDMI in a single case. I will be running the whole thing under an AMD 2050X Threadripper on 64 GB DDR4 on a Gigabyte Designaire motherboard. So that’s my plan…3 displays, 2 GPU’s from opposing camps, all on the latest hardware. My 34 in is my primary display and only nVidia will be powering this under proprietary drivers (especially gaming). My other two display’s are my multi-taskers when I’m doing a project, and so, I’m not concerning with anything but 1080p for these.

Reasons for both cards in the same box: If I had to sum it up in a single word: versatility. I plan to run a variety on distro’s on bare metal…some for testing and some full time using a partitioning scheme between 25 TB using 4 drives (2 spinning and 2 NVMe SSD’s)…and I want my display’s to always work…having both in my box allows me to switch to ALL nVidia or ALL AMD depending upon the requirements of each distro (god hoping none require integrated Intel graphics…cuz their aren’t any of that in my build).

My question: "Will most modern Linux distro’s boot up using both cards simultaneously & will I be able to exchange windows between my main nVidia screen and my 2 smaller 1080P Vega screens with no issue?

Note: I’m aware that Mesa drivers are in the kernel for Radeon and getting better and better every day under Linux…but I still feel they can’t compare to a 1080Ti running proprietary drivers for Linux Gaming for the way I game…using Steam. Which is why I didn’t go AMD all the way…just most of the way. Also, having two independent GPU’s allows me to dedicate one to a Virtual Session of Windows under Linux with some Voodoo…and I plan to do just that for some use cases.

Mainly, I’m just worried about issues arising from having arch-rivals running the same 3 screen setup under a single session of Ubuntu or Mint or Fedora or Arch (and yes, I plan to install and run ALL of these on the same box using this setup).

Thanks for any insight you, the community, can give me.

Please, no all RED Team or all GREEN Team people telling me why I’m misguided in doing both…only technical arguments or insights need respond.

Thanks in advance, guys.

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Best of Luck! Just getting dual gfx with Kavari and an R7 250 on Win10 gave me a headache…this is wayyy out of my league!

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My situation is not exactly the same as yours. I have a Radeon RX 580 and a GTX 1050 Ti in the same box. I use the Radeon for Fedora 28, and the 1050 Ti is reserved for a Windows 10 VM via vfio. My PC was NOT happy with the Nvidia proprietary driver installed, but that seemed to be because it was trying to grab the Nvidia GPU despite it being reserved for the VM.

Based on my experience, I don’t think your experiment will turn out too well. Then again, my implementation is different than yours…

EDIT: I think your chances of the two playing nice together would be if you use open source drivers for both GPUs. But nouveau is lacking in the performance department…

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So, for your nVidia / Radeon setup…have you attempted one monitor on nVidia & one on Radeon under Linux? I get the whole “reserve for VFIO” goal but have you tried DisplayPort on nVidea and HDMI on Radeon (or visa versa) on your box? If so, what issues did you encounter?

I can’t see myself rocking a 1080Ti on a G-Sync display just to choose Nouveau on Linux. I didn’t just spend $1K on a display & $800+ on a Asus ROG GPU for Nouveau. Nope… :wink:

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Can’t blame you for not wanting the performance hit of Nouveau. :slight_smile: But my experience with the nvidia proprietary driver has not been positive.

My setup is a bit weird. Until very recently, I had an ancient, but still beautiful, 30" Dell Ultrasharp 1600p monitor. Its critical flaw is that its single input is DVI dual link. So I had a DVI cable from each GPU going into a mechanical switch, and then I switched GPUs with the push of a button. I honestly do not remember trying to use both GPUs with a unified X windows desktop.

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I don’t see why it wouldn’t work.

In xorg.conf there are sections for “Monitor” “Device” and “Screen”

Monitor, we all know what that is.

Device would be the gpu, and Screen would determine which monitor uses which device.

I know the gpu’s will work without X. Many people have a mixture of GPU’s in linux machines crunching Boinc projects.

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Good to know that it really won’t matter under Linux. That was my gut (which is why I spent $1400 on 2 GPU’s vs $1300 on a single 2080Ti)…I simply couldn’t see myself spending that level of dough on a Pre-Ordered GPU that was getting uncertain performance reviews. Besides, I can do more with a AMD / Nvidia combo under Linux for the same investment…and get more out of it in performance depending on how I plug my cables in per X-session.

So, you’re sayin’ I should have no issues flinging windows around between 2 competing GPU’s with differing connections to each display under a single X-session under Linux?

@wendell

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I’m not positive. I’ve never tried it. I’m just thinking in theory, it might work.

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I was just browsing the Gentoo forums and found this

https://forums.gentoo.org/viewtopic-t-1085178.html

Someone has an nvidia gpu and intel Igpu running with 2 different monitors.

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Hey I know this is a little late, but I just wanted to post that I recently had to boot off of an Ubuntu Live USB, and both GPUs were recognized and outputting to my monitor. I didn’t have any vfio/iommu parameters in GRUB, and both video cards sent a signal to the monitor.

EDIT: However, this was with amdgpu and nouveau. Not sure about the nvidia proprietary driver.

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@imrazor - We’ll this is reassuring. I plan to rock Kubuntu 18.04 with as modern a kernel as they’ll make available to me via Synaptic with my Vega 64 rocking Mesa drivers on HMDI running two 24.5 in displays (and I’ll be FreeSync Capable when it comes to Linux via Mesa) and a single 34.5 in curved G-Sync display on DisplayPort running from a nVidia1080 Ti with the latest drivers available from them. That being stated, I have no qualms about going all Vega or all nVidea depending upon the distro limitations but my main system will be Kubuntu (for now) with a plan to migrate to Arch eventually. Your efforts give me reassurance that both my cards will do just fine. Thanks.

1 Like
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So, I finally built the beast. A 1080Ti & Vega 64 (both Asus ROG Strix cards each with their own x16 slot). I did indeed put my two 25 in displays on Radeon & my single 34 in curved display on Nvidia.

But now I have a problem. This whole time I was operating under the belief that Ubuntu with the latest Nvidia 390.78 drivers (or later) would be a slam dunk and I would have a god-like Linux Gaming monster. Buuut, Ubuntu does not wanna boot the Gnome DE on these drivers; what’s more, LightDM won’t load either. I tried Mint…and it loads only to crash Cinnamon session. But in each respect…when I simply go all Team Red…Vega 64…no problems. Did I miss a trend where Nvidia is now the enemy of Linux Gaming?

I really am now in search of a Distro that can handle a 390.78 (or later) driver load and runs Steam Client with performance. Please help.

System Specs:

Mobo: Gigabyte X399 Designaire (@wendell suggestion)
Processor: AMD 2950X Threadripper (Enermax AIO cooled)
Memory: 64 GB DDR4 GSkill (8x 16 GB Dimms)
Video Card’s: Asus ROG Nvidia 1080Ti
Asus ROG AMD Radeon Vega 64
Storage: 2 TB Samsung 970 NVMe
2 TB Samsung 970 NVMe
12 TB Western Digital Gold
12 TB Western Digital Gold
Display’s: Alienware 34 in Curved G-Sync Display
2 x Alienware 25 in Free-Sync Display’s

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Your Edit was prophetic, sir. I cannot, for the life of me, get a stable Ubuntu system to boot a Gnome or Cinnamon session with my 1080Ti once I load the Proprietary Drivers. I am so pissed.

That being said…my Free Sync display running Mesa drivers are as stable as anything. In fact, if I had only Nvidia…it would just boot to a black screen and that would be it. Having both cards and drivers running simultaneously has shown me this difference.

Now I’m just not sure where to go from here. Will I need to forsake G-Sync under linux and just go All Team Red or Red/Green Nouveau? I am so upset.

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Have you tried adding nomodeset to your kernel boot parameters?

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Ummm no. Forgive a newb question but what does that do?

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It stops the linux kernel from automatically assigning the nouveau driver to the GPU. If the kernel assigns nouveau to the GPU first, the correct driver wont load.

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Huh…ok. Well, tonight I’ll reload Ubuntu 18.04 LTS and do ALL the updates. Then I’ll re-add Nvidia driver 390.78, lookup how to add this nomodeset trick and report back.

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So, in Linux Mint, adding nomodeset after quiet splash in the grub file after installing the driver (and updating grub) caused my Nvidia GPU to completely fail, one of two of my HDMI Displays on my Radeon GPU to fail, and my Cinnamon session to regress into legacy. And so, I re-edited the grub file to delete the nomodeset, & restored the Nouveau driver. Rebooted. But the problem persists. So I then issued a: sudo apt remove nvidia-* Then rebooted and it restored the desktop. So, this tells me it’s something with my GPU on proprietary Linux Nvidia drivers. It’s so broken that I must purge the driver from the system to fix the Ubuntu-based distro. So I have no faith that this trick will fix anything with Ubuntu proper. But hey, I’ll still try.

I’ve had the new PC for a week and all I’ve done is fight with Ubuntu vs really use it as intended. My thoughts are that I need to just go all in on Team Red and only use Team Green when I dual boot into Windows. That being said, I would still prefer to use my Nvidia GPU on Linux with Steam; I just do not see a clear path to do that so far.

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have you tried installing the nvidia driver manually from outside of the repos? I would suggest trying that or removing nouveau again and trying that.