Need help with iMac 8,1 (early 2008) with EXP GDC through mpcie on Big Sur
 
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Need help with iMac 8,1 (early 2008) with EXP GDC through mpcie on Big Sur  

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Neutro
(@neutro)
Active Member
Joined: 2 weeks ago
 

Hey guys!

First of all sorry if it's the wrong place to post but since my setup is kinda out of the ordinary but it's still on mac i thought that was where this topic belonged Smile

I have a 2008 iMac (iMac 8,1) which i managed to successfully pair with a GTX670 though the mini-pcie slot or the iMac (used for the wifi card originally) using an EXP GDC Beast adapter:

This setup works on the last native version of Mac OS for this iMac model: El Capitan. I managed to run Unigine benchmark with 60+ fps on the external screen with it Smile

For this to work i had to install Nvidia Web Drivers using https://github.com/goalque/automate-eGPU (i had to manually hack the script to force gpuid and vendorid because it was originally designed for TB3 so it wouldn't detect my GTX 670 since it is connected through mpcie and not TB3):

This is what is displayed on the system info on El Capitan when the egpu is plugged in:

I'm trying to make this work on Big Sur. I've installed Big Sur 11.3 using OpenCore Legacy Patcher and it works properly (except for GPU acceleration, which is why i'm trying to make the egpu work with it).

When I try to boot Big Sur with the egpu plugged in, Big Sur loading screen freezes at this part:

However if I start the iMac with the egpu plugged in but then disconnect the egpu just before Big Sur loading screen reaches this part, it starts sucessfully and this is displayed on the GPU hardware info:

Aucune kext n'est chargée = "No kext is loaded"

So it seems like Big Sur is detecting the egpu but fails to load it, perhaps because no nvidia web drivers are installed?

I've tried to find a way to install web drivers on big sur but everything fails, i've tried utilities found here but they're all designed for TB3 and so they dont work with my egpu since it's connected to mpcie.

So i'm kinda stuck here 🙁

Could anyone help me with this? Thanks!

2016 14" Dell Latitude E7470 [6th,2C,U] + GTX 670 @ 4Gbps-M.2 (EXP GDC 8.5c) + Win10 [build link]  

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Neutro
(@neutro)
Active Member
Joined: 2 weeks ago
 

Update: i've tried to use Open Core Legacy Patcher number 3 option in menu (post install volume patch) and to my surprise after this the GTX 670 is detected and GPU acceleration is working on the desktop (using the integrated radeon, not the egpu).

However if i run unigine benchmark it's not using the egpu and i can't find an option to force the egpu to be used first (no option in power saving, alt apps not detecting the card since it's not in TB3).

Anyone know how i could do this? Thanks again Smile

 

2016 14" Dell Latitude E7470 [6th,2C,U] + GTX 670 @ 4Gbps-M.2 (EXP GDC 8.5c) + Win10 [build link]  

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Neutro
(@neutro)
Active Member
Joined: 2 weeks ago
 

Well i guess it's not possible because it's not TB3 native... Too bad! 

At least i've tried!

2016 14" Dell Latitude E7470 [6th,2C,U] + GTX 670 @ 4Gbps-M.2 (EXP GDC 8.5c) + Win10 [build link]  

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