Hello,
your build is very nice 😀. My configuration is not that impressive, but I am using the small version of your mainboard (romed8u-2t). There is one issue I am facing and not able to resolve. Have you tried passing through a GPU in the first PCIE slot? I cant get it working. The host is using the internal BMC graphics for boot and when it is up. Both external GPU are correctly taken over by vfio and can be passed throught to any Windows VMs, except when they are plugged into the first PCIE slot. In this case Windows is booting up only in save mode, without any graphics driver.
Thanks!