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Help! iMac 27" now thinks it is 18" after eGPU install
 

[Solved] Help! iMac 27" now thinks it is 18" after eGPU install  

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DANgerous25
(@danfalconar)
Estimable Member
Joined: 3 years ago
 

Hello all,

Got a horrible problem (now solved, but leaving this post for reference for others).

Set up my new eGPU with my iMac, using goalque's automategpu script. Worked perfectly for my external monitor, however my iMac 27" screen now thinks it is an 18" screen, even after everything uninstalled. See image attached.

My original setup: MacOS Sierra 10.12.3 | Late 2014 iMac 27" 5k | AMD Radeon R9 295X 4096MB

My eGPU setup: Akitio Node | EVGA GEForce GTX 980 TI (Classified?) | eGPU -> Apple TB3->TB2 Adapter -> MDP on iMac | Dell P715Q external display (connected to eGPU via DP -> DP)

Here's what I did to get it working in the first place: 

  • All eGPU disconnected from iMac
  • Restart iMac in recovery mode, disable SIP using "csrutil disable" in the terminal
  • Clean shutdown of iMac
  • Plugged in eGPU via MDP -> TB2/TB3, powered on
  • Started iMac in BAU mode
  • Akitio Node detected in System Report, GTX 980 TI not detected at this point
  • Follow goalque's instructions to run the automateGPU script, no problems encountered
  • Restarted iMac
  • External Dell display now works perfectly, including eGPU acceleration
  • Main iMac display thinks it is 18" - eek!

Here's what I've tried to fix it (unsuccessfully)

  • Changed the screen resolution via the System Preferences -> Displays: No good, because MacOS thinks the screen is 18" wide as so any changes in resolution just fit the 18" screen
  • Unplugged all eGPU stuff: No change
  • Restarted: No change
  • Changed nVidia driver settings to use OSX driver instead of nVidia: No change
  • Uninstalled nVidia driver using it's uninstall in the utility: No change
  • Reset the NVRAM and SMC: No change
  • Searched the web for similar problems: Can't find anything

Please also note that I did exactly the same procedure to install the eGPU using my Late 2016 13" MacBook Pro (only this time using pure TB3) which worked perfectly in MacOS and didn't leave me any residual screen issues.

Hopefully some of you experts out there can help me solve this one, my iMac screen is quite laughable at the moment and I really need to fix it!

Edit 23/4/2017: Solution for 5K iMac: Rastafabi's solution - Using the referenced post I'm now able to use eGPU almost completely naturally. It's a very stable and easy to implement solution. This has probably given my iMac a few more years of usefulness.

Thanks,

Dan

screen probs

late-2017 27" iMac Pro RPVega64 + [email protected] (AKiTiO Node) + MacOS 10.13.2
late-2014 27" iMac 5k R9 M295X + [email protected] (AKiTiO Node via TB3->TB2 adapter) + macOS10.13 & Win10


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goalque
(@goalque)
Noble Member Admin
Joined: 3 years ago
 

This is a known issue:

https://github.com/goalque/automate-eGPU/issues/17
https://egpu.io/forums/mac-setup/automate-egpu-sh-is-reborn-with-amd-polaris-fiji-support-for-macos/paged/2/#post-2292

 If you want to preserve the eGPU screen output:

  • Don’t use -skip-agdc option
  • Sleep & wake -> this possibly gives 4K
  • On macOS Sierra: sudo nvram boot-args="nv_spanmodepolicy=1", restart and report what happens

 

http://barefeats.com/mpt5k.html

https://www.tonymacx86.com/threads/5k-resolution-5120x2880-via-nvidia-drivers-on-dell-ultrasharp-27-monitor.158311/

automate-eGPU EFIapple_set_os.efi
--
2018 13" MacBook Pro + Radeon [email protected] + Win10 1809


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DANgerous25
(@danfalconar)
Estimable Member
Joined: 3 years ago
 

Thank you very much for your response (and your work) goalque. Ok, here's where are now:

  • After uninstall, I edited line 62 of the script to config_board_ids=(). Rebooted, reinstalled, no change.
  • I didn't use the -skip-agdc option in the first place (I didn't know I was supposed to nor do I have any clue what it does). Or was I supposed to somehow disable it?
  • Sleep & wake: Yes, my viewable screen now fills the iMac display. However as you say, it looks to be 4k and doesn't have the correct default resolutions. However, it's much better than where I was.
  • I did the sudo nvram boot-args etc. Didn't make any difference that I could see.
  • Also I do note that on the links you sent me, they seem to refer to Dell 5k monitors. Mine is 4k, not sure if that makes any difference. But in any case, I don't have a problem with this monitor. I'm not sure what to do with those links?

Any idea how to restore my iMac screen to how it was in the first place, even if I have to abandon eGPU for now? (I can use my MBP which is actually faster but less convenient, I'm guessing because of TB3 in MBP vs TB2 in the iMac).

Thanks again for your help.

late-2017 27" iMac Pro RPVega64 + [email protected] (AKiTiO Node) + MacOS 10.13.2
late-2014 27" iMac 5k R9 M295X + [email protected] (AKiTiO Node via TB3->TB2 adapter) + macOS10.13 & Win10


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goalque
(@goalque)
Noble Member Admin
Joined: 3 years ago
 

It’s advisable in the first place to use -skip-agdc with the 5K iMac. It does the same as line 62 fix but won’t give Nvidia eGPU screen output. The internal screen resolution will stay correct.

The boot-args nv_spanmodepolicy=1 is worth trying. We don’t know yet how it spans the content across the internal 5K screen when the eGPU monitor is plugged in and set as the primary.

Try also check/uncheck "Displays have separate spaces" in Mission Control.

If the nv_spanmodepolicy won’t restore the original resolution when the eGPU monitor is plugged in, try SwitchResX or reinstall macOS.

automate-eGPU EFIapple_set_os.efi
--
2018 13" MacBook Pro + Radeon [email protected] + Win10 1809


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DANgerous25
(@danfalconar)
Estimable Member
Joined: 3 years ago
 

Thanks goalque. Perhaps stupid question, if using -skip-agdc doesn't give Nvidia eGPU screen output then what's the point of doing it at all?

  • btw. the check/uncheck spaces has no effect.
  • SwitchResX helps to get a sensible resolution back (only after doing sleep/wake), but I don't think it restores the original 5k resolution.

So I'm now going to try a restore of MacOS Sierra. C0uld you outline the recommended steps from a clean install for the 5k iMac setup, to use the eGPU on the external monitor? I know you've given me lots of commands/things to try in the various posts, but would be good if we could try them out in the sequence that you think is best. Ultimately I don't want to lose my original 5k screen when doing this, and would prefer to avoid the sleep/wake partial workaround. + if there is any way to undo the install that kills the screen resolution, that would be far preferable to a MacOS reinstall!

Thanks again, Dan.

late-2017 27" iMac Pro RPVega64 + [email protected] (AKiTiO Node) + MacOS 10.13.2
late-2014 27" iMac 5k R9 M295X + [email protected] (AKiTiO Node via TB3->TB2 adapter) + macOS10.13 & Win10


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goalque
(@goalque)
Noble Member Admin
Joined: 3 years ago
 

Macs are not meant for gaming. You can use the eGPU for GPGPU tasks:

https://egpu.io/forums/mac-setup/automate-egpu-sh-is-reborn-with-amd-polaris-fiji-support-for-macos/paged/2/#post-2289

If the nv_spanmodepolicy doesn't help, and your requirement is the internal 5K, unfortunately you can't use the external monitor.

Download the script again, I made a minor change.

- Reinstall macOS
- sudo ./automate-eGPU.sh -skip-agdc
- Restart 

automate-eGPU EFIapple_set_os.efi
--
2018 13" MacBook Pro + Radeon [email protected] + Win10 1809


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DANgerous25
(@danfalconar)
Estimable Member
Joined: 3 years ago
 

Thanks, will give it a go. It will take a little while but I'll report back in this thread with whatever happens.

late-2017 27" iMac Pro RPVega64 + [email protected] (AKiTiO Node) + MacOS 10.13.2
late-2014 27" iMac 5k R9 M295X + [email protected] (AKiTiO Node via TB3->TB2 adapter) + macOS10.13 & Win10


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DANgerous25
(@danfalconar)
Estimable Member
Joined: 3 years ago
 

Download the script again, I made a minor change.

Hi goalque, I just want to check that I'm downloading from the right place, as for some reason my "diff" on the script I was using and the one I've downloaded from  https://github.com/goalque/automate-eGPU is giving some very weird output. Visually the scripts looks very similar but I guess there is some parameter somewhere changed.

Also want to confirm the sequence of spanmodepolicy change, should I do that before or after running your script?

Seems that there are quite a few people out there with the same problem as me, I haven't seen anyone with a bulletproof solution (5k on the iMac screen, accelerated eGPU on the external monitor). Happy to be your tester for the script/changes, goalque.

Cheers again.

late-2017 27" iMac Pro RPVega64 + [email protected] (AKiTiO Node) + MacOS 10.13.2
late-2014 27" iMac 5k R9 M295X + [email protected] (AKiTiO Node via TB3->TB2 adapter) + macOS10.13 & Win10


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goalque
(@goalque)
Noble Member Admin
Joined: 3 years ago
 

This was the change:

https://github.com/goalque/automate-eGPU/commit/88ef45911936047704173cd6e0e29d9f204b6e9a

I didn't test it.

You should do the spanmodepolicy change after running the script.

automate-eGPU EFIapple_set_os.efi
--
2018 13" MacBook Pro + Radeon [email protected] + Win10 1809


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DANgerous25
(@danfalconar)
Estimable Member
Joined: 3 years ago
 

Thanks, one more thing I want to check: A lot of the resources you've pointed me to refer to Dell 5k monitors. Mine is a Dell 4k monitor, not 5k. Does the spanmodepolicy change still apply/work and is the thinking that it stops the screen res reset on the internal 5k display?

late-2017 27" iMac Pro RPVega64 + [email protected] (AKiTiO Node) + MacOS 10.13.2
late-2014 27" iMac 5k R9 M295X + [email protected] (AKiTiO Node via TB3->TB2 adapter) + macOS10.13 & Win10


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goalque
(@goalque)
Noble Member Admin
Joined: 3 years ago
 

I have no experience with iMacs.

When your 4K eGPU monitor is set as the primary display, the apps on your internal 5K are rendered by the eGPU, therefore I just thought this spanmodepolicy may help.

automate-eGPU EFIapple_set_os.efi
--
2018 13" MacBook Pro + Radeon [email protected] + Win10 1809


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itsmikerofl
(@itsmikerofl)
Trusted Member
Joined: 3 years ago
 
Posted by: goalque

 

This is a known issue:

https://github.com/goalque/automate-eGPU/issues/17
https://egpu.io/forums/mac-setup/automate-egpu-sh-is-reborn-with-amd-polaris-fiji-support-for-macos/paged/2/#post-2292

 If you want to preserve the eGPU screen output:

  • Don’t use -skip-agdc option
  • Sleep & wake -> this possibly gives 4K
  • On macOS Sierra: sudo nvram boot-args="nv_spanmodepolicy=1", restart and report what happens

 

http://barefeats.com/mpt5k.html

https://www.tonymacx86.com/threads/5k-resolution-5120x2880-via-nvidia-drivers-on-dell-ultrasharp-27-monitor.158311/

   

Hi goalque! I adore your work! Picking up an iMac 5K tomorrow, planning on using the iMac with internal display over BootCamp with a GTX 1080 eGPU.

I see that you have a couple options that are specifically implemented for the iMac 5K - where should I start? Want to make sure things all go as planned and there are no problems, as this is my first experience with eGPU.

 

EDIT: Relocated to separate thread and added more background info.

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


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DANgerous25
(@danfalconar)
Estimable Member
Joined: 3 years ago
 

Hey @itsmikerofl, you might want to start a new thread for your question as your questions/upcoming issues are not the same as you'll experience as per the original post. I'll be interested to follow that thread though, as I also can't get the eGPU working under bootcamp on my iMac 5k. 😉

late-2017 27" iMac Pro RPVega64 + [email protected] (AKiTiO Node) + MacOS 10.13.2
late-2014 27" iMac 5k R9 M295X + [email protected] (AKiTiO Node via TB3->TB2 adapter) + macOS10.13 & Win10


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DANgerous25
(@danfalconar)
Estimable Member
Joined: 3 years ago
 

Hi @goalque et al., well the good news is that I've recovered my system. The bad news is that I still can't get it working how I want (i.e. accelerated eGPU driving my Dell 4k external monitor, non-accelerated internal GPU driving my internal iMac 5k screen at 5k/"retina" resolutions). The average news is that in response to my original problem, using @goalque's newer script version and instructions, I can get 4k resolution on my internal iMac screen whilst my eGPU drives the external monitor as desired without having to do sleep/wake. However I can't get "retina" resolutions on the internal iMac screen, even using QuickResX (which is cool, btw.). Unfortunately this setup just doesn't work for me.

So I've now uninstalled everything and I'm back to square one. Hopefully there's a solution in the works somewhere...

late-2017 27" iMac Pro RPVega64 + [email protected] (AKiTiO Node) + MacOS 10.13.2
late-2014 27" iMac 5k R9 M295X + [email protected] (AKiTiO Node via TB3->TB2 adapter) + macOS10.13 & Win10


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tsladamus
(@tsladamus)
New Member
Joined: 2 years ago
 

bumping this -- I am considering a very similar build (late 2014 imac with r9 m295x), thinking about using akitio node + tb3/tb2 apple adapter + belkin 2m tb3 cable. External monitor --> egpu for gaming and rendering and internal m295x for driving the retina built in imac display.

When you used the updated script, was your internal imac display limited to 4k resolution because your external monitor also just so happened to be 4k resolution?

Any updates since your last post?

Any info appreciated, thanks!

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


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DANgerous25
(@danfalconar)
Estimable Member
Joined: 3 years ago
 
Posted by: tsladamus

 

bumping this -- I am considering a very similar build (late 2014 imac with r9 m295x), thinking about using akitio node + tb3/tb2 apple adapter + belkin 2m tb3 cable. External monitor --> egpu for gaming and rendering and internal m295x for driving the retina built in imac display.

When you used the updated script, was your internal imac display limited to 4k resolution because your external monitor also just so happened to be 4k resolution?

Any updates since your last post?

Any info appreciated, thanks!

   

Short answer: no progress.

Long answer: it's possible that my external 4k monitor is the reason that the internal iMac screen gets limited to 4k, however I don't have another monitor to prove or disprove. 

I don't recommend this setup. Even to get 4k to work on the iMac screen (persistently) you have to use a screen res tool and have to put the iMac to sleep then wake to activate it. Plus the 4k looks pretty terrible on the iMac screen. 

Another point worth considering: I also have a mbp 13tb, if I hook that up to the 4k screen using thunderbolt 3 the performance is dramatically better than the iMac performance over thunderbolt 2. So that's what I'm using now for my egpu setup now. The iMac downsides are too great at the momenT

late-2017 27" iMac Pro RPVega64 + [email protected] (AKiTiO Node) + MacOS 10.13.2
late-2014 27" iMac 5k R9 M295X + [email protected] (AKiTiO Node via TB3->TB2 adapter) + macOS10.13 & Win10


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tsladamus
(@tsladamus)
New Member
Joined: 2 years ago
 

Thanks for that info! So I've been looking at MBP late-2016 models, but one big question remains:

With your mbp 13tb, do you have to leave it plugged in to the egpu all the time?

When you want to use the egpu, can you just connect the tb3 cable and use it on the external monitor pretty much instantly, or do you have to do a complete shutdown (and close all your apps?), then connect the tb3 cable, then boot the mac for the egpu to work on the external display ?

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


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DANgerous25
(@danfalconar)
Estimable Member
Joined: 3 years ago
 

Good question. You can plug it in any time but it won't work until you do a restart. If you unplug it while it's working it causes instant auto reboot. 

Personally I don't find this particularly inconvenient. I only plug it in when I want to egpu, otherwise I just use my iMac

Really hoping for someone to solve the iMac issues so it can just stay on all the time in a big multi screen setup!

late-2017 27" iMac Pro RPVega64 + [email protected] (AKiTiO Node) + MacOS 10.13.2
late-2014 27" iMac 5k R9 M295X + [email protected] (AKiTiO Node via TB3->TB2 adapter) + macOS10.13 & Win10


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DANgerous25
(@danfalconar)
Estimable Member
Joined: 3 years ago
 

I'm pleased to say that finally I have a solution which is 99% perfect, thanks to work from Rastafabi (see this thread). The missing 1% is the need to sleep/wake to get the internal iMac screen working, and whilst the OP of the aforementioned thread has provided a solution to semi-automate that process you still need to log in twice. It's really a very very minor inconvenience.

late-2017 27" iMac Pro RPVega64 + [email protected] (AKiTiO Node) + MacOS 10.13.2
late-2014 27" iMac 5k R9 M295X + [email protected] (AKiTiO Node via TB3->TB2 adapter) + macOS10.13 & Win10


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i0ntempest
(@i0ntempest)
Trusted Member
Joined: 2 years ago
 

How did you even make the eGPU to work? I have an iMac 2017 with Radeon 560, plus 1070 and Akitio Node, used goalque's script. Then my eGPU became visible in System Information but the screen connected to it simply stays black. Did I do anything wrong?

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 Mojave 10.14.6, Windows 10 1809, Kali Linux 2019.2
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 Beta, Windows 10 1903


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DANgerous25
(@danfalconar)
Estimable Member
Joined: 3 years ago
 

Hi there, I wrote this guide to explain how I did it. Note though there's one change since I did that, which is to enable FileVault encryption first. I recommend doing that before you do anything with the GPU. Do note however, that your iMac is 2017, mine is 2014 so I really don't know if they are comparable.

I wrote an update in this thread as to how I uninstalled and re-installed everything using the FileVault. I recommend reading both aforementioned threads and then giving it a go.

Good luck!

Edit: Removed some incorrect text in response to the previous poster's text that I misread.

 

 

late-2017 27" iMac Pro RPVega64 + [email protected] (AKiTiO Node) + MacOS 10.13.2
late-2014 27" iMac 5k R9 M295X + [email protected] (AKiTiO Node via TB3->TB2 adapter) + macOS10.13 & Win10


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