Hello!
So I have more or less completed my build and wanted to report back on some things I've found out that could potentially might help other people.
Catalina with the new AMD Radeon 5700 series
- 5700 series are supported on Catalina 10.15.1 out of the box (but needs WEG 1.3.4 and agdpmod pikera on the boot flags). However the installer has a bug so you can't use this GPU to install Catalina. I had to use the iGPU for that and then change it to the 5700. If you are doing an upgrade it shouldn't be a problem, just make sure you have WEG 1.3.4 and the boot flag.
- Avoid using iMacPro1,1 SMBIOS with Catalina 10.15.1 and the 5700 Series. It will freeze/kernel panic after sleep. My workaround is to use iMac19,1 or just disable sleep. This is already fixed on Catalina 10.15.2 beta 1.
- Catalina 10.15.2 beta 1 fixes the installer problem, but well... it's a beta release. So if you wan to go stable, upgrade from Mojave to Catalina and it will work just fine.
FAQ on Gigabyte Titan Ridge running on an Asus motherboard
- Did you have to install Windows? No, I haven't installed Windows so far to "enable" the card as some guides suggest. I'm not saying it's not always necessary but looks like on my build is not needed.
- How do you have your TB3 card connected? It's on the latest x16 slot. The TB3 header is also connected as well as the USB header. PCIe power is also connected, but I think this is more for Power Delivery capabilities. I don't know if this works as I don't have any device to test it
- Does this card works natively on macOS? Yes, this is the same chip some of the new Macs use. If you get the Alpine Ridge card instead (previous version) it will work too.
- Why do you even bother with this card? It's the only way to get the LG Ultrafine 5k running at full REAL 5k. In order to do this you require to have 2 DisplayPort-in which both the Alpine and Titan Ridge provide.