What is considered a high CPU usage?

High CPU usage typically refers to a sustained CPU utilization level above 80-90%. At this level, the system may experience performance degradation, lag, or unresponsiveness. However, what constitutes "high" can vary based on the application and system workload; for instance, intensive tasks like video rendering can naturally lead to higher CPU usage without indicating a problem. Regular monitoring and context are essential to determine if high CPU usage is a concern.