The PXE Representative is a very light install and does not use much in the way of resources at all. I have seen issues in some network where if they have a group of machines trying to hit it at the exact same time some of the machines will not properly resolve the PXE Rep as it will be to busy to respond to all the requests at once. So staggering booting up the devices is preferable.
You can install the PXE Representative on a VM if desired, just make sure the Network is setup so that VM has its own network connection that is not inside of a NAT.
Let us know if there is anything else.