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MP 1,1-5,1 Can Nvidia and AMD cards coexist in the same machine?

D

Demigod Mac

macrumors 6502a
Original poster
Apr 25, 2008
843
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In an attempt to add a few more years onto my 5,1's lifespan, thought of this:
  • Install a single slot RX 550 4 GB for macOS; upgrade to Mojave, possibly Catalina later on
  • Continue using my current MVC-flashed GTX Titan X for Windows/Gaming purposes
  • Use a KVM to swap between the video cards' displayports after switching OS
Has anyone tried something like this? I have an IPS G-Sync monitor that I'm very happy with so I'd rather not get rid of the Nvidia card. The macOS apps I use are not particularly demanding in terms of 3D performance.
Mainly wondering if having two cards from competing vendors could cause problems in either OS or on the  boot screen.
 
only you will stay at high sierra
mojave does not allowed mix GPU

unless you remove all nvidia kext from system extensions
would try this on a test system

but I can't say for sure if that will work
 
Demigod Mac said:
In an attempt to add a few more years onto my 5,1's lifespan, thought of this:
  • Install a single slot RX 550 4 GB for macOS; upgrade to Mojave, possibly Catalina later on
  • Continue using my current MVC-flashed GTX Titan X for Windows/Gaming purposes
  • Use a KVM to swap between the video cards' displayports after switching OS
Has anyone tried something like this? I have an IPS G-Sync monitor that I'm very happy with so I'd rather not get rid of the Nvidia card. The macOS apps I use are not particularly demanding in terms of 3D performance.
Mainly wondering if having two cards from competing vendors could cause problems in either OS or on the  boot screen.
Click to expand...

Looks like a bad idea. At least upgrade to Mojave or later is a bad idea for this multi GPU config.

You better just keep using HS and only use the Titan X.
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IndioX said:
only you will stay at high sierra
mojave does not allowed mix GPU

unless you remove all nvidia kext from system extensions
would try this on a test system

but I can't say for sure if that will work
Click to expand...

That should work, because there is simply no driver for Titan X in Mojave. So, no conflict between the RX550 and Titan X drivers. But I can't guarantee that MVC Mac EFI won't cause any issue in this situation.

However, IMO, keep the Titan X electrically connected inside a computer without proper driver loaded is a very bad idea. There will be no proper power management available for the graphic card. It may draw much more power than normal idle. The GPU may stay warm. We also don't know if there is any proper fan control.

For flashed card, it can display, however, that's it. It won't change the fact the no proper power management for the card. To use it in short period is no big deal (e.g. use it to boot recovery partition, or use boot manager, etc), but use the card like this for prolong period of time doesn't sounds like a good idea to me.
 
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h9826790 said:
That should work, because there is simply no driver for Titan X in Mojave.
Click to expand...
Titan always overrides the video outputs and the RX-580 does not output anything. I am 100 % sure there is some blocking in the software to not let that happen. I tried GT-640+Titan+RX-580. Nvidia always wins.
 
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startergo said:
Titan always overrides the video outputs and the RX-580 does not output anything. I am 100 % sure there is some blocking in the software to not let that happen. I tried GT-640+Titan+RX-580. Nvidia always wins.
Click to expand...
There is NO driver for the Titan X in Mojave, how can it override anything?
 
h9826790 said:
There is NO driver for the Titan X in Mojave, how can it override anything?
Click to expand...
What I meant by "override" is that only Nvidia card outputs to a display. None of the AMD outputs have signal to the displays.
 
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And the funny part. As we all know Apple stopped supporting Nvidia after HS. Yet Nvidia is preferred card in a dual setup with AMD. Go figure. During update of the OS (even in Catalina) both NVIDIA and AMD coexist peacefully and provide signals to their respective outputs. Same in recovery mode.
 
Demigod Mac said:
In an attempt to add a few more years onto my 5,1's lifespan, thought of this:
  • Install a single slot RX 550 4 GB for macOS; upgrade to Mojave, possibly Catalina later on
  • Continue using my current MVC-flashed GTX Titan X for Windows/Gaming purposes
  • Use a KVM to swap between the video cards' displayports after switching OS
Has anyone tried something like this? I have an IPS G-Sync monitor that I'm very happy with so I'd rather not get rid of the Nvidia card. The macOS apps I use are not particularly demanding in terms of 3D performance.
Mainly wondering if having two cards from competing vendors could cause problems in either OS or on the  boot screen.
Click to expand...

One thing you might want to consider in a mixed GPU configuration in a System is what happens if rendering data gets accidentally sent to the wrong GPU . It will crash the program and end your rendering session or maybe even kernel panic the Mac .
 
startergo said:
What I meant by "override" is that only Nvidia card outputs to a display. None of the AMD outputs have signal to the displays.
Click to expand...

You tested that in Mojave?
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startergo said:
And the funny part. As we all know Apple stopped supporting Nvidia after HS. Yet Nvidia is preferred card in a dual setup with AMD. Go figure. During update of the OS (even in Catalina) both NVIDIA and AMD coexist peacefully and provide signals to their respective outputs. Same in recovery mode.
Click to expand...

I wonder if that's web driver's issue.

When I mix GT120 (Nvidia) with RX580 (AMD) in High Sierra, my RX580 can display, but haven't have that "override" issue.
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IndioX said:
will probably be driven by the gforce or nvidia kext in system/library/extensions
Click to expand...

I wonder which kext will be loaded for Titan X in Mojave or later.
 
Demigod Mac said:
In an attempt to add a few more years onto my 5,1's lifespan, thought of this:
  • Install a single slot RX 550 4 GB for macOS; upgrade to Mojave, possibly Catalina later on
  • Continue using my current MVC-flashed GTX Titan X for Windows/Gaming purposes
  • Use a KVM to swap between the video cards' displayports after switching OS
Has anyone tried something like this? I have an IPS G-Sync monitor that I'm very happy with so I'd rather not get rid of the Nvidia card. The macOS apps I use are not particularly demanding in terms of 3D performance.
Mainly wondering if having two cards from competing vendors could cause problems in either OS or on the  boot screen.
Click to expand...

I run both an Nvidia GT120 and an AMD RX580 8Gb together under High Sierra and while they can coexist somewhat together and display 2 separate screens, they present certain issues with applications that use videotoolbox and will always default to Nvidia even if the RX580 is present. If you disconnect the display from the Nvidia card, then it will choose the RX580. If you have an adapter present connected to the Nvidia, it will default to Nvidia. If you have a KVM switch installed, it will default to Nvidia. Basically I can't have anything attached to the Nvidia card at all, otherwise it will default to Nvidia and create a ghosting distortion effect on most graphical programs including the finder under High Sierra. The reason I kept the Nvidia GT120 is basically for boot screen and updates. I also plan to upgrade the GT120 to a GTX680 for one application that will utilize CUDA cores for transcoding, but it needs to be in HS because of the web driver support, but it will only work if I have no screen, adapter or even a monitor switch attached to it. I have a digital monitor switch in my monitor to switch between 3 inputs and that causes havoc with both my Nividia and AMD. Hope this helps.

So yes, mixing AMD and Nvidia together is not recommended unless you have specific rendering needs.
 
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h9826790 said:
You tested that in Mojave?
Click to expand...
Both Mojave and Catalina. Of course there are no web drivers for both operating systems, but video is accelerated, and the card is reported Metal. I don't know what driver is loaded. Bear in mind I am talking about Kepler Titan.
 
startergo said:
Both Mojave and Catalina. Of course there are no web drivers for both operating systems, but video is accelerated, and the card is reported Metal. I don't know what driver is loaded. Bear in mind I am talking about Kepler Titan.
Click to expand...

Titan X has accelerated display in Mojave and Catalina? It's the very first case I know.

Edit: Oh, just see that you are talking about Kepler. Then how can it related to OP's question? OP's card is Titan X. Which is NOT supported in Mojave and Catalina at all. Completely different than Kepler's case.
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Please, can we stick with OP's hardware, but not something else has completely different supportability in Mojave or Catalina.

This cause a lot of confusion.
 
As far as I understand it, Nvidia cards that has the Kepler architecture will have native support in both Mojave and Catalina like the Titan (not Titan X which is Maxwell based). Which is probably why Titan is accelerated under Mojave. Another card that has native support is the GTX680 under Mojave as well. Both Nvidia and AMD can coexist together and can provide displays under Mojave and certain software like Davinci Resolve Studio can use both Nvidia and AMD cards together and leverage better video rendering speeds. The problem with the OP's Titan X is that, it is not supported under Mojave. It is supported under High Sierra, but will face issues with having 2 cards as I experienced with both my GT120 and RX580 coexisting together. However, I only use a few applications that behave nicely with both cards. As soon as I use other applications that don't play nice with both cards, I have to pull out the GT120.
 
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What about a Vega II Duo while on macOS and Titan RTX while booted into Windows/ Bootcamp? Will the RTX be automatically disabled while on Mac and vice versa in Windows?
 
Romanesco said:
What about a Vega II Duo while on macOS and Titan RTX while booted into Windows/ Bootcamp? Will the RTX be automatically disabled while on Mac and vice versa in Windows?
Click to expand...

RTX can’t work in MacOS is expected. However, I don’t think really at the “disabled” state, but more like an unknown state due to electronically connected but no driver. And MacOS cannot disable a graphic card in device manager like Windows.

In Windows, the OS should try to install the applicable driver for the Vega automatically, but this function can be disabled. The user can also manually disable the Vega in device manager.
 
h9826790 said:
RTX can’t work in MacOS is expected. However, I don’t think really at the “disabled” state, but more like an unknown state due to electronically connected but no driver. And MacOS cannot disable a graphic card in device manager like Windows.

In Windows, the OS should try to install the applicable driver for the Vega automatically, but this function can be disabled. The user can also manually disable the Vega in device manager.
Click to expand...

Will the RTX card degrade hardware-wise when disabled under macOS use?
 
Snazzy Labs tested an Nvidia card in a 7,1's Bootcamp mode and it worked. No mention if the cards fight over which one drives macOS though.

 
Only solution that I can come up with for this setup of a gt630 with boot screen and rx580 is to use bootpicker for windows which will see and use the radeon.

One display setup on this system so plug into the radeon in windows. Forget doing anything requiring graphic power in macos.

Less than ideal.

Is this thread going to be the final word on the subject? No chance of a different better workaround?
 
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