This MB supports GPU passthrough on PCI slots 1 & 4 with PCIe ACS Override off, I was able to pass through a nVidia GTX 980ti on slot 1 without needing to dump the video BIOS with a video card also in slot 4 and the MB BIOS set to use slot 4 as the primary graphics card. This presented the only IOMMU grouping that allowed passthrough with PCIe ACS Override off - I haven't experimented yet with the different overrides yet.   BIOS Settings to enable VM support (bold settings) & S