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pmraiders
(@pmraiders)
Active Member
Joined: 2 years ago
 

I've seen it mentioned several times that there is some sort of conflict between DGPU and EGPU usage in Bootcamp. I'd like to know a little more about this issue. Here is my setup so we are on the same page:

2018 15" MBP, Radeon 560x DGPU
MSI Gaming Box RX580

Windows 10 Pro, no modified bootloader at the moment, no enabling of IGPU, though I can enable that with one terminal command. I chose to DDU my drivers, then have both the EGPU and DGPU enabled and attached when installing the community sourced bootcamp AMD drivers. This actually appears to have successfully installed an identical driver version for both cards, they both show up in device manager and are NOT yellow banged. When the EGPU is connected there is no display on the internal display. Rebooting and unplugging the EGPU prior to windows loading throws me into a completely functional windows environment with fully accelerated DGPU graphics. No disabling of PCIE lanes for the DGPU though my x4 connection on the right side of the laptop is disabled to avoid yellow-bang.

So I've seen people mention a driver conflict, but I am using one driver that drives both adapters individually, so what exactly is the conflict with getting them to work together? How do the crypto guys get multiple cards to work in a single system? Unfortunately I am recently returning to the AMD realm, and only for seamless unmodified MacOS compatibility.

2018 Macbook Pro 15" - i7 2.6ghz - Radeon Pro 560x
Gigabyte RX580 Gaming Box


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itsage
(@itsage)
Illustrious Member Admin
Joined: 4 years ago
 

The driver conflict is mainly due to Apple's use of dGPUs that are classified as "Radeon Pro" in their Macs. The provided Boot Camp drivers are for these dGPUs only. The drivers for AMD eGPUs are usually stock AMD Radeon drivers and they don't work with the Pro dGPUs. That's why we need DDU to rid the systems of Boot Camp graphics drivers then use modified Radeon drivers for both dGPU and eGPU. In short it's basically this:

  • Boot Camp drivers «» Apple Radeon Pro dGPU only
  • Stock Radeon drivers «» AMD Radeon eGPU only
  • Modified Radeon drivers «» AMD Radeon dGPU & eGPU

external graphics card builds
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eGPU enclosure buyer's guide

 
2020 13" MacBook Pro [10th,4C,G] + RX 5700 @ 32Gbps-TB3 (Prototype eGPU Enclosure) + macOS 10.15.4 & Win10 1903 [build link]  


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pmraiders
(@pmraiders)
Active Member
Joined: 2 years ago
 

So that explains why the modified drivers work for both. So why are both adapters not functional simultaneously? Even if only the dgpu is accelerating the internal display?

2018 Macbook Pro 15" - i7 2.6ghz - Radeon Pro 560x
Gigabyte RX580 Gaming Box


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OliverB
(@oliverb)
Noble Member
Joined: 2 years ago
 
Posted by: pmraiders

So that explains why the modified drivers work for both. So why are both adapters not functional simultaneously? Even if only the dgpu is accelerating the internal display?

Because in these setups a part of it *must* be bad. It's like ying and yang:

-nVidia is much better for Windows, but way much worse for MacOSX.
-Radeon is much better for MacOSX, but really a shame under Windows.

2018 15" MBP & 2015 13" MBP connected to RTX2080Ti GTX1080Ti GTX1080 Vega56 RX580 R9-290 GTX680

 
2018 15" MacBook Pro (RP560X) [8th,6C,H] + RX 5700 XT @ 32Gbps-TB3 (ASUS XG Station Pro) + Win10 & macOS 10.15.4 [build link]  


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mac_editor
(@mac_editor)
Famed Member Moderator
Joined: 3 years ago
 
Posted by: pmraiders

So that explains why the modified drivers work for both. So why are both adapters not functional simultaneously? Even if only the dgpu is accelerating the internal display?

Seems to be a firmware problem on the 2018 MBPs.

purge-wranglertbt-flashpurge-nvdaset-eGPU
Insights Into macOS Video Editing Performance

Master Threads:
2014 15-inch MacBook Pro 750M
2018 15-inch MacBook Pro

 
2019 13" MacBook Pro [8th,4C,U] + RX Vega 64 @ 32Gbps-TB3 (Mantiz Venus) + macOS 10.14.6 & Win10 [build link]  


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itsage
(@itsage)
Illustrious Member Admin
Joined: 4 years ago
 

@mac_editor Have you tried booting into Windows with EFI Boot Manager? I no longer have a 2018 15" MacBook Pro but I think doing that with disabling the PCIe Root Port to wireless cards and PCIe Controller to unused Thunderbolt ports may free up enough resources for AMD eGPU.

external graphics card builds
best laptops for external GPU
eGPU enclosure buyer's guide

 
2020 13" MacBook Pro [10th,4C,G] + RX 5700 @ 32Gbps-TB3 (Prototype eGPU Enclosure) + macOS 10.15.4 & Win10 1903 [build link]  


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mac_editor
(@mac_editor)
Famed Member Moderator
Joined: 3 years ago
 

@itsage I think I had tried that but will give it shot again when I can.

purge-wranglertbt-flashpurge-nvdaset-eGPU
Insights Into macOS Video Editing Performance

Master Threads:
2014 15-inch MacBook Pro 750M
2018 15-inch MacBook Pro

 
2019 13" MacBook Pro [8th,4C,U] + RX Vega 64 @ 32Gbps-TB3 (Mantiz Venus) + macOS 10.14.6 & Win10 [build link]  


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ICULikeMac
(@iculikemac)
Estimable Member
Joined: 3 years ago
 

I have a 2017 15" MBP w/ R560 & XG Station Pro with a Vega 64 and have got it working in windows. I will post details if needed.

2019 Razer Blade Stealth GTX1650 Win10
Aorus Gaming Box RTX 2070
Asus XG Station Pro (RX570 8GB + RTX 2080)


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itsage
(@itsage)
Illustrious Member Admin
Joined: 4 years ago
 

@iculikemac The 2018 15" MacBook Pro is in a different situation. So far it's not possible to attach the iGPU to the internal display at all.

external graphics card builds
best laptops for external GPU
eGPU enclosure buyer's guide

 
2020 13" MacBook Pro [10th,4C,G] + RX 5700 @ 32Gbps-TB3 (Prototype eGPU Enclosure) + macOS 10.15.4 & Win10 1903 [build link]  


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pmraiders
(@pmraiders)
Active Member
Joined: 2 years ago
 
Posted by: itsage

@iculikemac The 2018 15" MacBook Pro is in a different situation. So far it's not possible to attach the iGPU to the internal display at all.

That would be the ideal solution... I'm going to go out on a limb and call this a bug, but has the community ever seen bugs like this fixed by apple? Is this the first time something like this has happened? Perhaps macos handles display attachment in a nonstandard way?

2018 Macbook Pro 15" - i7 2.6ghz - Radeon Pro 560x
Gigabyte RX580 Gaming Box


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