System in question -
ASUS P9X79-E WS
AMD FirePro W7000
Intel Core i7 4930K
240GB SSD / 3TB HDD
macOS Sierra 10.12.6
I have everything working on this build via two custom SSDTs, minus the onboard ASM1042 3.0 controller which I have hard-disabled via the motherboard's UEFI and replaced via a SIG PCI-E ASM1142 3.1 controller add-on card which has native OS X driver support & works flawlessly.
Here's the rub - whenever I enabled "Above 4G decoding" in the UEFI on this motherboard it works in Windows 10 fine but in OS X it hangs in boot at "PCI devices Configuration" - the system won't boot with the AMD controller kext initialized.
I have a Broadwell-E build (6850K) - MSI X99-A Raider that has "Above 4G decoding" as an option. If I plug my FirePro into that machine running macOS 10.12.6 it boots OS X just fine. However I've chosen to stick with my Ivy-E build for now due to issues the Broadwell-E build has with Sleep/C-states at times in OS X - they work but intermittently they break.
For instance after say 13 sleep/wakes on the X99 machine - there is a chance it will reset the machine entirely and begin a fresh boot-up sequence. It's weird...Is there anyway I can patch Clover/the OS X system to Force 4G decoding on the X79 build? Am I missing something? A patch I can apply to the DSDT? An ACPI Table I should drop? I am grasping at straws I rarely post so posting is like a last resort believe me.
Additional Info -
I'm using no ATI injector/running Whatevergreen.kext (allows working sleep and complete DP recognition + etc) Tried FirePro's UEFI BIOS with and without (legacy mode) Have tried npci=0x2000/0x3000 , Inserting Clover driver "EmuVariableEFI" with and without. All current CloverConfigurator patches with and without.
-Have also added my current EFI folder to this post. Any/all help greatly appreciated! I am very certain this pertains somehow to how the system handshakes with the videocard - not sure why it differs between this X79 & why the X99 build I have is allowing it on OS X.