Q. If I set a Hyper-V processor reserve for a virtual machine (VM), does it mean this processor percentage is unavailable to other VMs?

A. When you set a VM reserve, you guarantee that the VM will always have access to that amount of CPU resources. However, if the VM isn't using the full reserve, other VMs may access the processor resource. As soon as the VM with the reserve needs the CPU, it will take priority and be guaranteed its full allocation.