Hi
@CaseySJ,
First off, thanks a lot for such a fantastic guide. This has been very helpful.
This is a little weird time to buy a GPU. The AMD is releasing Big Navi on 28th and performance looks promising. So I thought I'd wait for it now. However, my original plan was to get Nvidia 3080 for Windows and use iGPU for Mac, and resort to second dGPU, RX 580 if I couldn't able to make iGPU work on macOS.
Luckily I've been able to fix iGPU, on i9-10900K. And thought I'd share my findings here to make this Golden Build even more golden.
As suggested by many posts here in this thread, in current state, just using the Intel-config-plist from post #1, the iGPU processes simply crash when opening anything that use hardware acceleration, like Safari. Heck, even a simple text editor, Sublime 3 refuses to start and crashes. A simple test I've been using is to go to chrome://gpu URL in Google Chrome. It should show all GPU stats. Prior to fixing the iGPU, the logs said the GPU process on Chrome crashes and it had to resort to Software only decoding (see attached screenshots below). The problem was that Chrome recognizes the GPU as its original PCI Device ID 0x9BC5 which is headless GPU in iMac20,2 (which I'm using as SMBIOS). But since Lilu and WhateverGreen sets it up as non-headless GPU and hence it must be crashing.
So the simple solution was, along with platform-id, add 'device-id' as same model. I've used 0x9B3E0000 (screenshot attached). This matches the platform-id being used. Now, Chrome and other apps recognizes this GPU as 0x9B3E (screenshot attached) and is hardware accelerated, and every app which uses GPU no longer crashes. Again I don't have any dGPU installed at all. Sublime no longer crashes. Safari no longer keeps reloading the page when loading page containing something GPU oriented. Intel Power Gadget shows GPU frequencies touching up to 5 GHz (which is little weird, maybe this is normal in non-headless mode). NVIDIA Geforce NOW which I use to play games online from the cloud, starts working. It just simply crashed without device-id. A 4K HEVC video works smoothly in QuickTime which I see is a test used here by people. I even tried it at 10x seek speed and it doesn't flick at all. I'm liking this kind of power. Just imagining what Radeon 6000 series can do.
I understand that this guide and Intel only GPU testing was done prior to release of iMac 2020 and Catalina with proper support. But this works for me for time being, and I hope it will be useful to people requesting to make the iGPU work properly in non-headless mode. I've been using this for over a week and every animation is smooth and had no problem at all. Even sleep/wake works (I don't have any Fenvi card yet though, I don't think I need it as OpenIntelWireless seems to fix bluetooth which is all I need for now, will wait it to be more stable perhaps, as I use Ethernet anyway).