Need help understanding ASUS ProArt B550 Creator IOMMU Grouping

Tech Specs in ASUS website

Hi everyone,

I am planning to buy a ASUS ProArt B550 Creator for VFIO and Looking Glass. This mobo supports PCIe 4.0 x8/x8 out of the box and is $135 from where I live. I want to put two GPUs on it.

Information about this mobo I found online:

Wendell’s review of the mobo, with IOMMU grouping
This mobo in linux-hardware.org

I specifically want to know the grouping on of the x8/x8 CPU PCIe lanes (to see if I can pass one GPU to VM and keep the other one on host). Sadly I am unable to determine this from the materials above.

Could anyone help me with this? Thanks!

This is a video about the BIOS settings of this board:

Link

There is an option “ACS Enable”. I guess this is relevant?