I had wanted to get an iMac for an eGPU implementation in a while. The mid 2017 refreshed iMac with Thunderbolt 3 is perfect timing. I got the base 21.5″ 4K which has the Radeon Pro 555 dGPU. It came from the factory with 10.2.4 so Goalque‘s automate-eGPU script should work fine under macOS. My priority is to get this iMac going in Windows 10.
One bad news is that Apple firmware completely disabled the iGPU in this iMac. I could not see it in either macOS or Windows (using goalque’s guide). Therefore, the discrete graphics card Radeon Pro 555 is only one running all the time. That means AMD XConnect and Nvidia Optimus for internal display acceleration is not possible in Windows.
…unless you follow enjoy’s excellent trick to force the eGPU accelerate the internal display with a headless display adapter. Here are the steps I took in order to get an Nvidia GTX 980 Ti going with this 2017 iMac 4k:
- Download Windows 10 ISO and install through Boot Camp Assistant.
- Allow Apple Boot Camp drivers to finish installation and shut down.
- Use a delay boot to hot plug the eGPU (OPTION key to select Windows volume, hot plug eGPU when Windows logo appears).
- Open Device Manager and right click on Microsoft Display Adapter and proceed to let Windows download the right drivers.
- Shut down and use delay boot to hot plug eGPU.
If all goes well the Nvidia eGPU should be fully functional with an external display after these 5 steps. I did not encounter error 12 with one eGPU. When I paired two eGPUs with this iMac, error 12 became an issue. For internal display eGPU acceleration, please read enjoy’s guide. Here are my screen captures of the setup. Look at HWiNFO64, the Thunderbolt 3 PCIe lanes attach directly to the quad-core i5 CPU.
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So, this is working on the internal display, with Win 10 at 4K?
2017 15" MacBook Pro 2.9GHz Core i7, Radeon Pro 560, OWC Mercury Helios FX 650, Sapphire RX590 8GB, ASUS MG24UQ
So, this is working on the internal display, with Win 10 at 4K?
Yes it does. As mentioned in my original post, it’s a current workaround by following enjoy’s guide to force the eGPU accelerate the internal display via a headless display adapter. Another limitation is “window mode” only for gaming.
I’m not sure why Apple disabled the iGPU on this mid-2017 iMac. If you have a mid-2017 iMac, please check System Information » Graphics/Displays and let us know whether iGPU is present.
Mine is a 2015. I haven't tried it yet, TB2 being a huge reason.
2017 15" MacBook Pro 2.9GHz Core i7, Radeon Pro 560, OWC Mercury Helios FX 650, Sapphire RX590 8GB, ASUS MG24UQ
I agree. On older Thunderbolt connection, force-feeding the signal back to the internal display will absolutely negate eGPU performance gain.
In macOS, headless display workaround has a performance hit of 30-50%. I would imagine it’s similar in Windows. I will try external display this week to get some idea on this mid-2017 iMac 4k.
Cool! Thanks for ALL you and the guys are doing for the Mac Community.
2017 15" MacBook Pro 2.9GHz Core i7, Radeon Pro 560, OWC Mercury Helios FX 650, Sapphire RX590 8GB, ASUS MG24UQ
I agree. On older Thunderbolt connection, force-feeding the signal back to the internal display will absolutely negate eGPU performance gain.
In macOS, headless display workaround has a performance hit of 30-50%. I would imagine it's similar in Windows. I will try external display this week to get some idea on this mid-2017 iMac 4k.
@itsage It's a bummer that a headless adapter is needed for internal display support. I was hoping it would be possible without one, but my former 2014 5k retina only listed the dGPU as well. I don't think the 2017 iMac's are unique in this regard as this is an issue with other iMacs and the 2013 Mac Pro as well.
Do you foresee any possibilities to go around this (i.e. did you try disabling the dGPU once you got the eGPU setup working on boot? --or would that shut off internal display?
I'm interested to see the external display performance. I'm eying a 2017 5k retina, but I need to justify that egpu performance (e.g. 1080 ti, upcoming Vega) would outweigh the internal Radeon Pro 580 for future-proofing.
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I ran some quick benchmarks to compare Radeon Pro 555 dGPU vs GTX 980 Ti eGPU with external display. If you reference to the internal display eGPU results in my original post, it’s about a 50-60% drop in performance. I really wish Apple had enabled the iGPU in this iMac firmware. Nvidia Optimus would have reduced that performance loss to 10-15%.
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Thank you. I'm looking forward to your result.
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Same here!
Would be intressting to see the performance difference with eGPU compared to the dGPU.
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I returned the iMac. I could not complete my tests because the hard drive speed was unacceptable. There’s no excuse for using a 2.5″ 5,400 RPM hard drive in Mac anymore. What a shame to pair a nice 4K display and Thunderbolt 3 with an extremely slow spinning drive.
How did u get eGPU to work in macOS? I have an iMac with Radeon 560, I used the automate-eGPU script but the external screens connected to the eGPU simply won't light up. Please help! Thanks!
Setup 1: Apple iMac 2017 21.5” 4K + eGPU
dGPU: AMD Radeon Pro 560
eGPU: ASUS Strix AMD Radeon Vega 56 via Thunderbolt 3 (AKiTiO Node)
OS: macOS Catalina 10.15.3, Windows 10 1809, Kali Linux 2020.1
Setup 2: Apple Mac mini 2018 + eGPU
iGPU: Intel UHD Graphics 630
eGPU: AMD Radeon RX 570 MXM via Thunderbolt 3 (Sonnet Breakaway Puck)
OS: macOS Catalina 10.15.4 Beta, Windows 10 1909
Out of interest, do you think it's actually even possible for Apple to enable the iGPU using a firmware update? Or is it very much a hardware thing? Just wondering because if it's possible to do without literally ripping the machine apart, perhaps some clever hacker can actually mod the firmware- although I understand this gets into dangerous territory on many levels.
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Hello!!
Has anyone successfully got an eGPU running on an iMac in BootCamp using the native display in the High Sierra GM?
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Hello!!
Has anyone successfully got an eGPU running on an iMac in BootCamp using the native display in the High Sierra GM?
Lol welcome to a world of pain. Check my last post here:
https://egpu.io/forums/mac-setup/imac-27-setup-internal-accelerate-possible/ to see the kind of difficulty it will be just to get anything working. Also, something no one seems to make clear - don't use the golaque script iirc - use the eGPU enabler here https://egpu.io/forums/mac-setup/imac-egpu-simply-for-3d-accelleration/paged/2/#post-19965
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Greetings and thanks to all the “explorers” of eGPU,
I have installed an AORUS GTX 1070 Gaming Box on an iMac 21″ 4K Late 2015 fast and hassle-free thanks to the @goalque guide from this review:
https://egpu.io/gigabyte-aorus-gtx-1070-gaming-box-review-tiny-but-mighty/
My doubts now are how to install egpu in Windows 10 whit Bootcamp, @itsage this is posibble for my iMac? Thanks
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Hi i am new here. What is a delay boot?
Thanks,
Hunk
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@Hunk89, a delay boot is a boot procedure when you hold the OPTION key to select a boot volume. Once the OS starts to load, you then connect the eGPU to the Mac.
Hey,
I am not keen to use these complicated guides from this website. 9to5Mac said that you simply connect it, install the drivers and it will go. Why so complicated?
I want the eGPU for my 2017 iMac 27" but ONLY for Windows (bootcamp)
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Hey,
my Radeon Pro 580 is present i n both windows and Mac OS. I am not keen to use these complicated guides from this website. 9to5Mac said that you simply connect it, install the drivers and it will go. Why so complicated?
I want the eGPU for my 2017 iMac 27" but ONLY for Windows (bootcamp)
Unfortunately petulance won’t win you anything with this, and you’ll need to do some reading to understand why it’s not that simple with an iMac 
it took me about two days to figure it out.
To help you out more though, tell me first what your end setup goal is- eg external monitor? TB3?Which GPU? Etc.
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I want to run an Gigabyte Aorus GTX 1080 Ti on internal display. TB 3. 2017 iMac
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I want to run an Gigabyte Aorus GTX 1080 Ti on internal display. TB 3.
OK then, youre going to have some challenges. I should also point out that if you want to run it internally there's literally no point in having a Ti, if you can refund and get a 1080 (or maybe even 1070) you'd do better saving the money - for now at least. The issue you're going to face is two fold - one, you can't disable the dGPU because iGPU activation isnt an option. The only way to make this work properly is by using a dongle as described here: https://egpu.io/how-to-egpu-accelerated-internal-display-macos/
I personally used a random one on Amazon which seemed to work fine. So you understand - there's no native way to make apps use the eGPU unless you do this, because the display is 'linked' the the GPU. To give you an understanding - if you were using an external display, the reason it's easier is because you can set the external display as the primary display in windows - it will then prioritise the eGPU. So what youre doing is mimicking the external display with a ghost adapter - whats cool is that Windows seems to understand that it's a ghost adapter and it runs relatively smoothly once you do this.
You'll also need to download the NVIDIA drivers for your card.
Once you've done that you'll need to sort Error 12- it's an easy fix (just disable a PCIE lane), and well covered here, but let us know if you don't know how.
Once that's done you should be pretty much up and running - and yes, there will be an improvement - but to be clear it is a HUGE performance loss from if you were using an external display. To give you an idea I was getting around 160fps on a game on an external display, and then about 100fps on internal. Still better than the Radeon though.
OK final thing - and this may not be an issue for you, but I never managed to fix it fully: On Windows, when you have an HDMI (even a ghost) from an eGPU Windows recognises this and defaults the audio through that. Fine right? You can just changed the audio output setting using the task bar thingy? Well - I couldnt. It showed the audio as playing through the internal speakers, and even through headphones, but the audio didnt some out. I tried reinstalling bootcamp drivers - this fixed the audio but resulted in me having other issues which put be back a few steps. I managed to fix it by using a USB DAC which I happened to have - so I was able to play through headphones; but if you're relying on your iMac speakers you may have issues.
Other notes - don't use the iGPU enabler scrip/usb thing - its not meant for iMac.
-You will have crashes and driver issues, this is normal, you'll probably often have to restart to fix.
So yes - it's all doable, and once you know how it's not even that hard - but it sure isn't 'natively supported', and whether the performance increase vs cost is worth it for you is up to you
Hope that helps!
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I also have a 2017 iMac with 580 and would like to egpu to the internal display. I've been reading these forums but am now starting to get confused on if this is really possible or even worth it if the performance hit is so great. I also found this method to enable the igpu on the Apple forums, do you think this would work?
The GPU on my mid-2011 27" iMac i7 died recently. Replacement for the 2 gig AMD Radeon HD 6970M 2048 MB card was around $840 locally, which represents around 35-40% of a new mid-2017 27" iMac i7. Although I had no issues with data lose (due to iCloud and Dropbox), I wanted access to my hard drive to at least erase it. I had read in other blogs that it is possible to boot with the integrated Intel graphics chip by eliminating the AMD/ATI extensions within the Systems library. Due to the addition of System Integrated Protection (SPI), using the Unix commands at the Single User Mode was not possible to move or delete the extensions in macOS Sierra, so the last resort was to directly access the HD using either a targeted drive boot with another Mac or use an external boot drive. I do not own a Thunderbolt cable, so i opted for the external boot drive, which I created with my MacBook Air. Here are the steps that I used to successfully reboot my iMac with the internal HD on the integrated Intel chip:
1. Create a boot disk using a different Mac: https://support.apple.com/en-us/HT202796
2. After creation, reboot your Mac (not the bad GPU Mac) and access the new boot drive. Under the folder System/Library/Extension, move or delete any file/folder that begins with either AMD or ATI. I elected to transfer them to a folder I created called DisabledExtensions.
3. Boot the discrepant iMac with the new boot drive by pressing the option key during the startup. This gives access to choose the startup drive.
4. Once fully into your iMac, log on to your HD (if required) and in the System/Library/Extension folder, either move or delete all references that begin with AMD or ATI.
5. Reboot the iMac. Hopefully, this will allow you to operate on the integrated chip. There will be some graphic issues, but, if all goes well, overall you will have full access to your data, as I did.
I abbreviated the steps with the idea that anyone following this blog will know I have shortcut some of the detail in creating boot disks and logging onto a system from an outside peripheral. However, it worked for me.
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-You will have crashes and driver issues, this is normal, you'll probably often have to restart to fix.
And thats already a no go. I am selling the iMAC, get a windows gaming Machine and keep my Macbook Pro. I will use a kvm switch for peripherals like mouse, keyboard, Printer. My Monitor can switch back and force between two inputs and my boxes also can do two inputs.
Thats a better solution for me.
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Hello All, I'm requesting advice if I should invest in the new GTX 1080 Gaming Box for 2017 iMac 27" with i7 and Radeon Pro 580 ? My goal is to run the internal display as I don't have desk space for another monitor. Will the performance gain be worth the cost & trouble? Or is the performance hit too great? I read on these forums the performance hit is much less when using 1440p or 4k resolutions. I plan to use these higher resolutions exclusively.
I'm currently getting ~7785 in Superposition with the default 1080p Medium setting. This is with a mild but stable overclock on the Radeon Pro 580, 1300/1800.
Thanks!
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i want to do this aswell, looks like as of now a headless display adapter is the only solution
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@nik-moretto The headless display adapter is the only workaround atm. This is a 50% performance loss vs. using the eGPU with an external monitor.
Is there any other workaround? or is that what we are limited to in bootcamp for now?
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Please help me. I'm stuck
Have exactly the same setup. Can see all monitors and videocards but I don't know how to switch between monitors. What should I use in windows options for several monitors? extend monitors? Duplicate monitors?
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