Windows Task Manager is lying to you, and I don't know how to make it stop
If you use Windows, you might be intimately familiar with Windows Task Manager, which has a performance tab that shows the utilization percentage of various hardware in your system. Today, we're looking at CPU utilization. It looks a bit like this: The problem is that the meaning of the word utilization is very tricky. There can be multiple meanings: At the current time, with the current settings, what fraction of time is it executing instructions vs lying idle? At any time, with the most optimum settings, this CPU could practically complete a number a instructions at a certain rate. What percentage of that rate is it currently working at? I think the Windows Task Manager is currently using definition #1 above. This is useful for a person to look at the graph and understand "is there a runaway process on my system that is pegging my CPU"? However, consider the alternate use-cases: I am trying to run a long-running program, am I getting my money's worth out of this CPU