AlphaVM by default always consumes 100% of the host CPU core, even when the guest OS (OpenVMS or Tru64) is idle. This is because the guest OS idle loop is code that does not do anything to release the CPU.
AlphaVM-Pro has a feature called the idle release. AlphaVM recognizes the idle loops of the supported guest OSes and releases the CPU for a short time quantum when the idle loop is hit.
This feature significantly lowers the CPU consumption of idle systems. As the result the electricity consumption is also lowered.