I have successfully created and used several CentOS 7 (1511/Minimal) HVMs. Intel i3 so no IOMMU. No TPM installed. Seems to work decent so far. 16GB RAM, I can have 3 CentOS HVMs open simultaneously, the work VM (with 4 terminals and Firefox), the Fedora 23 VM open (while doing an update on the Fedora 23 VM) and everything was still fairly responsive, very nice. I've had this machine loaded for about three months now.