On a real iMacPro1,1 and many of the new Macs where there's no IGPU, they do have the T2 chip (even one's with IGPU have T2 chip). Even if it is enabled, WEG Kext would setup a headless IGPU for you so no need to use it. It is not necessary since you disable it in the BIOS. There's nothing wrong with your config apart from the device properties you set for the IGPU. With FCPX 10.4.6 on Mojave 10.14.6 it's much better - at least HEVC encode works on RX580. What you are seeing with FCPX 10.4.8 on Catalina 10.15.4 is consistent with what I am seeing. H264 Encoding (low CPU load, fully utilization on RX 580) HEVC Encoding (CPU max out, low utilization on RX 580) Is there anything wrong in my config (attached)? any input is much appreciated. Suppose iMacPro1,1 should use dGPU to encode/decode HEVC and H264 because iMacPro is IGPU-less, correct? I know my i7-4790K Haswell lacks HEVC support and can only do H264. However, when doing HEVC encoding, dGPU (RX 580) is not fully utilized and my CPU maxed out on FCPX (10.4.8) and Compressor (4.4.6) on Catalina 10.15.4. So I switched from iMac15,1 to iMacPro1,1 and disabled IGPU in BIOS. Reading through pages in this thread, it looks like HEVC can be enabled as long as SMBios is iMacPro1,1 and IGPU disabled.
I still couldn't figure out how to enable HEVC support with RX 580 on 10.15.4. Thanks for this thread to give so much useful information. Does it mean to encode HEVC with RX 580 on FCPX or Compressor, I need to go back to Mojave? Does this issue only affect RX 580, but not other cards like 5700 XT? I tried again with Compressor (4.4.4) on 10.15.4 and still no luck. Building a CustoMac Hackintosh: Buyer's GuideĮdit: Just read through again in the thread, found macnb's post #1439 mentions FCPX 10.4.8 has issue with HEVC.