Available article translations:

My virtual machine consumes about 100% of the Mac CPU resources

  • Parallels Desktop for Mac Business Edition
  • Parallels Desktop for Mac Home Edition
  • Parallels Desktop for Mac Pro Edition


  • My computer fans speed up and Mac starts to heat up.
  • My virtual machine's process (prl_vm_app or Parallels VM) in the Activity Monitor consumes 100% of Mac CPU or above.


High CPU usage by virtual machine's operating system.


Maximum utilization of every CPU unit assigned to a virtual machine in Activity Monitor counts as 100%. For example, if your virtual machine has 4 CPU units assigned, then a total amount of CPU utilization by a VM will be 400%. To check how many CPU units are assigned to VM open configuration window > Hardware > CPU & Memory.

NOTE: We highly recommend using the recommended number of CPUs. Assigning more recommended number may cause performance degradation of both Mac and virtual machine.

Virtual machine's CPU consumption directly depends on guest operating system usage. If you notice that your VM consumes a high amount of CPU resources, check CPU consumption in guest operating system in Task Manager (right-click on Windows task bar > Task Manager):

Once you determined what process of Windows program consumes sufficient amount of CPU, you may refer to the software manufacturer knowledge base to find more information. For some types of software, like video or photo editing, CAD or videogames, high CPU usage is a common operation condition.

If you find that this process belongs to Windows OS, please note that the following system actions cause high CPU usage:

  • Downloading and installing Windows updates
  • File indexing
  • Driver incompatibility issues
  • Redundant startup applications

To find out the reason for high CPU usage in your case, note the process name and refer to Microsoft Support or a third-party resources for more information.

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