Performance of Parallels VM from Bootcamp partition vs. VM on macOS partition

Parallels allows us to run a Windows VM on macOS. On older Macs, we were able to run Windows on Boot Camp, which was an alternative to a VM. Interestingly, if we install Windows on Boot Camp we can, from macOS Parallels, run that Windows as a VM. Now to the question: we generally say a VM will be a little bit slower than Windows running directly on hardware. What about a VM from the Boot Camp partition vs. a VM on a macOS partition? Which one is supposed to be faster?