Here is the system specs:
ASRock AB350 Gaming K4
American Megatrends Inc., Version P6.40
BIOS dated: Mon 31 Aug 2020 12:00:00 AM CDT
Ryzen 9 3950x
32 GB 3000Mhz Dual channel ram
All SATA storage, 1 SSD for Cache, other HDD for storage drives.
Booting in Legacy mode.
Running Unraid 6.9.1.
After upgrading my CPU from a R7 1700 to the 3950x, I am not able to pass through my RX570 or GTX 1070 into a Windows 10 VM in either CPU connected PCI-E slot.
This board has 2 slots connected to the CPU, primary 16x slot and a 4x slot that shares lanes with an m.2 slot. I am not using the m.2 slot. I have attempted to use both slots with the GPUs. One GTX 960 2GB and either the RX 570 4GB or GTX 1070 8GB.
I am able to passthrough the RX570 or 1070 GPU into a Linux VM(PopOS) with no issue.
The behavior is that 1 or more CPU threads peak at 100% usage when the AMD GPU drivers load.
I did attempt this with a GTX 1070 and had similar results…
However, I was able to passthrough a GTX 960 in the 4x slot without issue in either slot.
So, I do not think this is related to the motherboard. Is it possible that the micro code on the 3950x does not handle the passthrough correctly? Or is this possible a limitation of Unraid with the R9 CPU? Is this an issue with booting in Legacy mode and not enabling above 4G decoding?
Any help would be appreciated.