You can't calculate the IDLE time unless you have the right tool. For the basic principle, the IDLE time of a process is calculated based on an interval of time and how many times the process was used. The process is in IDLE mode if the application corresponding for that process isn't used. You will need a tool to specifically monitor the idle time of a process. The application above switches the affinity and the priority of a process by setting some variables to increase the CPU power and allocation. This results in faster processing for the application, but the OS and other applications will suffer.