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Very strange eGPU behavior. Any suggestions?
 

Very strange eGPU behavior. Any suggestions?  

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Blakeanator
(@blakeanator)
Active Member
Joined: 10 months ago
 

Ok, so I’m praying there is some eGPU gurus on this forum 🙂 I need some input/advice so if anyone out there can shed some light on what I’m missing here, please chime in. It has been quite a journey for me in trying to figure this whole eGPU thing out.

To start, I just got a 2018 15 inch MBP and installed bootcamp for some work applications. Everything went as expected and it setup just fine. I then tried plugging it into my eGPU and monitor. This is where things got interesting.

At first I hot plugged it into the computer and it crashed Windows. So I downloaded the latest Intel thunderbolt and Radeon drivers (18.12.3), thinking that was what it was missing for the Vega 56 that was in the eGPU. After installing the drivers, hot plugging still didn’t work, but having the eGPU plugged in at boot seemed to work just fine. Both the internal display and the external monitor worked (although I’m sure the internal display wasn’t accelerated). The dGPU (a Vega 20) showed as having problems in the device manager and being disabled, but the Vega 56 now showed up and was functioning properly. There were a few weird quirks worth mentioning...

First off, the Vega 56 showed up in the device managers as “Vega RX.” Don’t know if this is actually a problem or not but it was odd to me as plugging in the same eGPU into another windows laptop I had showed both the sonnet enclosure and “Vega 56” in the device manager.

Also, I couldn’t plug anything else into computer while it was connected to the eGPU. Plugging in an external drive, for example, would either freeze the displays or crash windows. What was even more odd, however, was if I plugged the external drive into the USB port on my monitor (and if I was using a thunderbolt connection to said monitor) it would recognize the drive. It was only when I plugged something into any of the 4 thunderbolt ports on the actual MBP that windows would freeze or crash.

This was slightly irritating, but the setup worked and I was willing to put up with it. I have a wireless  keyboard and mouse that I used via Bluetooth anyways.

At some point, a few weeks into using this setup as described, my internal display on the MBP quit working. Again, I was really using the external monitor so this wasn’t a huge problem for me and I really didn’t take notice.

But here’s now the problem, it’s not that the internal display isn’t working when plugged into an eGPU (I don’t really use it then) it’s that Windows now acts like the internal display doesn’t even exist at all. So when I don’t use an eGPU and want to boot into bootcamp normally (disconnected from the eGPU and monitor), the MBP display is just dark. 

So, I searched online for solutions and that’s when I found this egpu.io site. After doing some reading the conclusion I came to was “well if the dGPU isn’t working solo anymore, maybe I can enable the iGPU.” So I then followed the tutorial on this site, downloaded and installed the Intel UHD 630 drivers, restarted, and used the EFI usb drive to attempt to get the internal display working. What ended up happening was the internal display glitching (looked like a old TV set with no signal) and the eGPU and monitor ceasing to work.

Sorry for the long story, but if you’re still with me my question is this: what should I try? Should I reinstall the default bootcamp drivers and just start trying stuff again? I’ve read online (from bootcampdrivers.com) that the Radeon 18.12.1.1 drivers and forward support the Vega 20 dGPU in the MBP, so why doesn’t the dGPU work at all?

I could always wipe and start over but my bootcamp partition is 2.5 TB and nearly full. It would be such a pain to redownload all that data but I’m happy to do it. I just need some clarity on what direction I should take.

Thanks,

Blake

Pending: Add my system information and expected eGPU configuration to my signature to give context to my posts


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itsage
(@itsage)
Famed Member Admin
Joined: 3 years ago
 

This is all expected behaviors on the 2018 15″ MacBook Pro with an AMD eGPU. Unlike 2016 and 2017 15″ MBPs, the 2018 firmware prevents the iGPU from powering the internal display. My recommendation is to boot back into macOS so that the system would force-attach the dGPU to internal display. You can then see whether it’s possible to boot into Windows. If you can, run DDU to uninstall all graphics drivers. Once you’ve done this, reinstall latest Radeon drivers from AMD website for the eGPU.

Best ultrabooks for eGPU use

eGPU enclosure buying guide


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Blakeanator
(@blakeanator)
Active Member
Joined: 10 months ago
 

Thank you itsage for your insight. I figure the T2 chip probably has something to do with it (even though I have it set on the lowest security settings).

I was actually able to run the bootcamp partition in parallels and run descrete.bat to get bootcamp to use the eGPU and external monitor again (the dGPU still doesn’t work). I’ll try your suggestion, two questions:

1) Would running DDU disable the current drivers for the eGPU and external monitor? If so, should I run DDU from safe mode or parallels? (I know the guide stays to do some of it in safe mode but I believe there are a few steps you are suppose to take before that point in the normal Windows environment, those are the steps I’m asking about).

2) You say this is expected behavior for an AMD eGPU. Would my results be different if I was using an Nvidia card? I thought Nvidia cards had extra steps to setup because of macOS not whitelisting them.

Thanks,

Blake

Pending: Add my system information and expected eGPU configuration to my signature to give context to my posts


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itsage
(@itsage)
Famed Member Admin
Joined: 3 years ago
 

If Parallels works for you, give that a try with DDU and let us know. It’s a nice convenience when it’s tricky to get back into Boot Camp. While Nvidia GPUs don’t have native eGPU support in macOS, they are actually easier to get working in Boot Camp. On the 2018 15″ MacBook Pro, an Nvidia eGPU doesn’t use as much resource and would likely allow the AMD dGPU to function.

Best ultrabooks for eGPU use

eGPU enclosure buying guide


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