Indicates a process that performs time-critical tasks that must be executed immediately for it to run correctly. The threads of a high-priority class process preempt the threads of normal-priority or idle-priority class processes. An example is the Task List, which must respond quickly when called by the user, regardless of the load on the system. Use extreme care when using the high-priority class, because a high-priority class CPU-bound application can use nearly all available cycles.