I believe this would fall under a motherboard/cpu issue (cause of iommu), but I'm not really sure
I bought a HP Elite 6300sff tower with an i5-3470 in it, both of which (tower, and cpu) support Intel Vt-D, I have it enabled in the bios, yet Unraid refuses to say that it is enabled, i have tried so many things, including adding "iommu=1 iommu=pt" in syslinux.cfg to no avail
Can anyone help? If not, ill try and contact unraid support.