the CPU shouldn't be limiting either.
KVM is a different solution, which may be used on any Linux, like Debian or Fedora.
Yes, Qubes is based on Fedora and XEN as the virtualizer. XEN is rather similar to KVM, though Qubes improves upon it in a multitude of ways, like isolating network cards from the rest of the host, not just the guests.
Have a nice day,