I am using iMacPro1,1 profile. I was able to overcome the freeze issue by trying other SMBIOS like iMac18,1, iMac18,3, etc. But I wanted to completely fix the issue so I just upgraded the card and now DRM is working perfectly.
Give this EFI folder a try. Back up your current one so you can restore it if this one does not work. You should be able to disable IGPU in BIOS. Once you have it disabled, WhateverGreen will do the rest in terms of renaming your discreet GPU to the correct name in Mac (eg, GFX0).
I am looking to upgrade my video card to a Vega one. Which one would you guys recommend I get? It will be a used MSI branded one and the price difference between the two is only $50. Is it worth spending extra $50 and get the 64 version one?