iMAC dGPU + eGPU help. How to get internal screen working?
 
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iMAC dGPU + eGPU help. How to get internal screen working?  

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abelviking
(@abelviking)
Eminent Member
Joined: 2 years ago
 

Hello,
So been at this for 3 days, about 14 hours really. Gotten the eGPU to work with the dGPU falling in the Code43 category. Done a LOT of reading, closests threads:
https://egpu.io/forums/pc-setup/how-to-keep-mbps-irisiris-pro-activated-when-booting-into-windows-boot-camp/ -> How to activate Internal display for Laptops ONLY, iMAC has its iGPU disabled by Apple's firmware.

Code 43 categories, dGPU and ePGU for NVIDIA NON thunderbolt PCI Express connections: https://egpu.io/forums/expresscard-mpcie-m-2-adapters/

Most important pieces of information so far are:

Posted by: itsage

Apple disabled the iGPU on all iMacs if they have a dGPU. apple_set_os.efi does not help

Posted by: geaguirre80

I thought this method worked for iGPU models only. I tried with a 2016 macbook pro 15" dGPU AMD 450 without luck. Instead I'm booting Windows 10 with CLOVER and custom DSDT and works pretty well.

So my question is, does anyone know of any iMAC build that does have 5K internal screen enabled, this one on the same environment I have (except he has a 1080ti and I have an RX 580) falls short at the internal black screen.
https://egpu.io/forums/builds/late-2015-27-imac-m390m-gtx108016gbps-tb2-aorus-gaming-box-via-tb3-tb2-adapter-win10-pravalorius/#post-56859

Sytem InfoiMAC Late 2015. dGPU AMD M390, OSX 10.12.6, Windows 17134.rs4_release.180410-1804(1803). GYGABYTE AORUS RX580 miniITX eGPU my signature

 
2015 27" iMac 5K (R9 M390) [6th,4C,] + RX 580 @ 16Gbps-TB2>TB3 (Gigabyte Gaming Box) + Win10 [build link]  


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Jyin
 Jyin
(@jyin)
Estimable Member
Joined: 3 years ago
 

Only way I was able to get internal screen working on my 2017 iMac 5k was
a) Use nVidia card in eGPU
b) Use the AMD card in eGPU and use the internal display as MS Basic Display at 4K by disabling the dGPU.

For 2015 iMac 5K, I was able to do (b), didn’t try the (a) option since I got my 2017 before I got my 2080ti.

J

2017 27" iMac 5K (RP580) [7th,4C,K] + RTX 2080 Ti @ 32Gbps-TB3 (Sonnet Breakaway 550) + Win10 [build link]  

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abelviking
(@abelviking)
Eminent Member
Joined: 2 years ago
 
Posted by: Jyin

Only way I was able to get internal screen working on my 2017 iMac 5k was
a) Use nVidia card in eGPU
b) Use the AMD card in eGPU and use the internal display as MS Basic Display at 4K by disabling the dGPU.

For 2015 iMac 5K, I was able to do (b), didn’t try the (a) option since I got my 2017 before I got my 2080ti.

J

How exactly did you go about doing that? When I disable the dGPU M390 no video is posted, either on external or internal. I'm using the bootcampdrivers.com and for the first time Device Manager sees both GPUs. Also, finally my internal screen is completely off but I'm having trouble in video games as both screens go off.

This post was modified 2 years ago

Sytem InfoiMAC Late 2015. dGPU AMD M390, OSX 10.12.6, Windows 17134.rs4_release.180410-1804(1803). GYGABYTE AORUS RX580 miniITX eGPU my signature

 
2015 27" iMac 5K (R9 M390) [6th,4C,] + RX 580 @ 16Gbps-TB2>TB3 (Gigabyte Gaming Box) + Win10 [build link]  


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

Windows 10 1803 and newer have Graphics Options to assign a particular graphics card for apps/games. As long as you can get both the dGPU and eGPU working in Boot Camp then you can use eGPU to accelerate the iMac's internal display.

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

 
2013 Mac Pro (FP D500 x2) [3rd,12C,E] + RX 5700 XT @ 16Gbps-TB2>TB3 (Mantiz Saturn Pro) + macOS 11 [build link]  


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Jyin
 Jyin
(@jyin)
Estimable Member
Joined: 3 years ago
 
Posted by: abelviking
Posted by: Jyin

Only way I was able to get internal screen working on my 2017 iMac 5k was
a) Use nVidia card in eGPU
b) Use the AMD card in eGPU and use the internal display as MS Basic Display at 4K by disabling the dGPU.

For 2015 iMac 5K, I was able to do (b), didn’t try the (a) option since I got my 2017 before I got my 2080ti.

J

How exactly did you go about doing that? When I disable the dGPU M390 no video is posted, either on external or internal. I'm using the bootcampdrivers.com and for the first time Device Manager sees both GPUs. Also, finally my internal screen is completely off but I'm having trouble in video games as both screens go off.

First thing you want to do is to make sure the eGPU works in OS X.
This will verify the Hardware is correctly put together and functioning.

Since you have Retail AMD card, you should be able to use the Retail Driver.
You will either have to use the Device Manager to install, or hack the installer config (super easy, search in my post history for how to do it).
For 2015 iMac, you will also have to perform DSDT override. There is a nice write up on how to go about doing that in this forum.

You will also want to read up on my build.
Specifically, try using the TB2 port close to the Ethernet Port. Make sure you don’t have anything else connected to the other port.
Try it with nothing in USB ports either, it might help, although those shouldn’t impact eGPU.

J

This post was modified 1 year ago
2017 27" iMac 5K (RP580) [7th,4C,K] + RTX 2080 Ti @ 32Gbps-TB3 (Sonnet Breakaway 550) + Win10 [build link]  

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

Try this Bootcamp guide.

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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abelviking
(@abelviking)
Eminent Member
Joined: 2 years ago
 
Posted by: itsage

Windows 10 1803 and newer have Graphics Options to assign a particular graphics card for apps/games. As long as you can get both the dGPU and eGPU working in Boot Camp then you can use eGPU to accelerate the iMac's internal display.

I recognize what you're talking about. I first saw it in an episode of Linus tech tips where they get a Bitcoin mining Nvidia GPGPU with absolutely NO ports to output video in TESTING mode through the Iris GPU. That left me dumbfounded because like YOU said in the enable iGPU guide, for iMACS apple disabled the iGPU. I wonder if it was because of the 5K display being too much for it....
I already found that option but my screen still goes black and I'm very bummed about that. I'm about to post my findings next. Is it true you need DSDT to remove error 12? That's where I'm confused. You'll see why in the following post.

This post was modified 1 year ago

Sytem InfoiMAC Late 2015. dGPU AMD M390, OSX 10.12.6, Windows 17134.rs4_release.180410-1804(1803). GYGABYTE AORUS RX580 miniITX eGPU my signature

 
2015 27" iMac 5K (R9 M390) [6th,4C,] + RX 580 @ 16Gbps-TB2>TB3 (Gigabyte Gaming Box) + Win10 [build link]  


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abelviking
(@abelviking)
Eminent Member
Joined: 2 years ago
 
Posted by: Jyin
Posted by: abelviking
Posted by: Jyin

Only way I was able to get internal screen working on my 2017 iMac 5k was
a) Use nVidia card in eGPU
b) Use the AMD card in eGPU and use the internal display as MS Basic Display at 4K by disabling the dGPU.

For 2015 iMac 5K, I was able to do (b), didn’t try the (a) option since I got my 2017 before I got my 2080ti.

J

How exactly did you go about doing that? When I disable the dGPU M390 no video is posted, either on external or internal. I'm using the bootcampdrivers.com and for the first time Device Manager sees both GPUs. Also, finally my internal screen is completely off but I'm having trouble in video games as both screens go off.

First thing you want to do is to make sure the eGPU works in OS X.
This will verify the Hardware is correctly put together and functioning.

Since you have Retail AMD card, you should be able to use the Retail Driver.
You will either have to use the Device Manager to install, or hack the installer config (super easy, search in my post history for how to do it).
For 2015 iMac, you will also have to perform DSDT override. There is a nice write up on how to go about doing that in this forum.

You will also want to read up on my build.
Specifically, try using the TB2 port close to the Ethernet Port. Make sure you don’t have anything else connected to the other port.
Try it with nothing in USB ports either, it might help, although those shouldn’t impact eGPU.

J

I just lost my reply to you. I have no idea why.
There's also a weird logic when posting that makes it impossible to write the space :' ' character in the last line. I was editing so perhaps it is related.
Also 8 out of 10 times I get a ReCaptcha v3 error on the log in screen. This is the only browser/computer combo I can log in with so far. Just sharing. I've no idea if it's common. Cookies, different browsers, etc, makes no difference when I try to log in through Windows. Perhaps that is it.

Back to topic. 

First things first:
Considering your build information. The AORUS, being a compact design, lacks a mechanical switch. Instead it uses a gate switch that turns the PSU on when it sees voltage on the TB3 port. I cannot plug in this eGPU and only turn it on once the OS comes up. I can risk sparks by using the power cord, but don't like the idea.

OSX.  Booting in OSX makes the Aorus go full LED on and crank the fan to 100%. Neither of those things happens in Windows. Obvioiusly System Manager only Sees the M390. Forgot key information here since I had to write this twice, the OSX version is 12.6

Side note: On a borrowed 2018 Macbook pro with an RX550 and an iris running OSX 10.13.6 the eGPU runs out of the box.

Key piece of information:
My Bootcamp is on UEFI, because I'm using Windows To go. That is I'm booting Windows from an USB 3 drive. Don't have enough space for actual bootcamp. I've read how important that is for settings things up properly when enabling the iGPU ( you need both rrRT(can't recall the name) boot manager updated for Mac firmware and the enable iGPU EFI script on the EFI partition of the USB drive) then load the enable iGPU script followed by loading Windows.

Because of that it means I must figure out a way to put the DSDT config in the EFI partition of my already existing USB driver. I don't think I can use two USB drives to load the DSDT from USB/EFi rather than firmware and risk bricking my expensive MAC like it is warned in the DSDT guide. Yes, DSDT makes me nervous and today I read through the guide. The safe way to do it is to use the installer by macuser that even deals with AMD and TB2 specifics to format an USB drive and place the assembly code(Intel approach for MAC) in Memory. I would then have to figure out how to transfer that onto the already existing EFI USB 3 SSD running Windows, like they did for making the Mac think is booting in OSX and how to revert back in case I need to. Might have to get VMWARE out again.

Onto the fun stuff, ready for a school project table?

@itsage This is where the confusion begins.

Preamble: different driver combinations give different results. I can get things to work only under two combinations, out of those none is fully satisfactory and one is playable, as in I can use it on an external display.

 

Driver Combination Error Code&Location Results Comment
1.-OSX downloaded Bootcamp 2015 for M390
2.-Windows Update downloaded 2017 for RX580
Code 43 on M390 1.-The iMAC's display backlight is ON
2.-There's no video data coming on the iMAC display
3.-XConnect XComes up
4.-External display comes up with configurable resolution in Game
Too risky to leave IPS burning out.
1.-2017 Windows Update driver for everyone Code 12 on Hotplug - RX580 1.-Computer won't boot on cold plug
2.-eGPU ATTEMPTS to send data over to external display(you see alert that no input is coming in go away and the backlights come up in external display: 1080p TV)
Disabling the M390 doesn't do anything.
Disabling Camera and other peripherals neither.
1.-2018 AMD site's Driver for Apple Computers - M390
2.-Windows Update 2017 RX580 driver
Code 43 on M390 Same as row 1. Blocking Windows Update from installing drivers from the Internet actually prevents XConnect/RX580 from ever coming up. That's how I figured the Code 43 must be due to driver conflict and that the Bootcamp Apple drivers don't support eGPU/XConnect.
1.-Bootcampdrivers.com Adrenaline 19.3.1 for Anyone Code 12 on RX580 on Hotplug 1.-On hot plug the ePGu goes into Code 12.
2.-After a COLD plug(rebooting with ePGU attached) both GPUs are detected. This is the same behavior a Macbook Pro user noticed with the same eGPU.
3.-Finally, the internal display is OFF.
1.-First time I did this I noticed how slow the fan was.
2.-The LED lights NEVER come up.
3.-AORUS Gaming engine(this thing comes with a DVD, ha!) which I downloaded from gigabyte. com doesn't load, be careful not to use Xtreme Gaming but get Gaming Engine instead.
4.-I opted to override the fan settings on the Radeon Control panel and saved some GPU-Z logs for RPMs/GPU temps. The thing went up to 750 RPM and kept the GPU between 60 and 76 Celsius.
5.-Is playable but I can't stand how sharp the image looks on a TV after being spoiled by the 5K screen for so long. I had been playing older games for a while and 2 GB from the M390 was fine up to that point. Only wish it was a real 390... but Apple can't take the heat (unless is an I7 on a Macbook) 😉 . HAD TO VENT OUT. Mr. Green Twisted

 

This post was modified 1 year ago

Sytem InfoiMAC Late 2015. dGPU AMD M390, OSX 10.12.6, Windows 17134.rs4_release.180410-1804(1803). GYGABYTE AORUS RX580 miniITX eGPU my signature

 
2015 27" iMac 5K (R9 M390) [6th,4C,] + RX 580 @ 16Gbps-TB2>TB3 (Gigabyte Gaming Box) + Win10 [build link]  


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abelviking
(@abelviking)
Eminent Member
Joined: 2 years ago
 
Posted by: OliverB

Try this Bootcamp guide.

So basically I'm doing on row 4 plus step 6 of guide B.

And then, I think I've done that before. Will have to try again, thanks! No DSDT, hmmm...

Sytem InfoiMAC Late 2015. dGPU AMD M390, OSX 10.12.6, Windows 17134.rs4_release.180410-1804(1803). GYGABYTE AORUS RX580 miniITX eGPU my signature

 
2015 27" iMac 5K (R9 M390) [6th,4C,] + RX 580 @ 16Gbps-TB2>TB3 (Gigabyte Gaming Box) + Win10 [build link]  


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Jyin
 Jyin
(@jyin)
Estimable Member
Joined: 3 years ago
 

The DSDT override was required for my 2015 iMac and the Vega.
Obviously your case ‘might’ not be, since it’s been over an year since I had it running on 2015, and you are on 580.

I never loaded the DSDT from EFI. I put the Windows on test-mode and load the DSDT from registry. That way, all you need to do is to disable the test-mode and you are back to factory DSDT.

Since the days I used the 2015, Apple have blocked the eGPU usage in OS X (on any Macs with TB2).
There is a script to get around that, I think it’s called purge-wrangler

You can always put the eGPU on power strip and use its switch to turn it on/off. That’s what I do, since my desk has one built-in with individual switch per outlet. 

Check this post out too.

https://egpu.io/forums/pc-setup/imac-27-2015-egfx-bb-550-vega-fe-lc/

J

This post was modified 1 year ago
2017 27" iMac 5K (RP580) [7th,4C,K] + RTX 2080 Ti @ 32Gbps-TB3 (Sonnet Breakaway 550) + Win10 [build link]  

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