What is Dynamic frequency scaling, idle state?

Dynamic frequency scaling changes a core’s clock (and voltage) while it runs, according to load, temperature, power budget and the number of active cores; the highest frequencies, called turbo, are available only while the package stays within its limits. An idle state (a C-state) is a low-power state a core enters when it has nothing to run, from which it takes microseconds to wake, deeper states taking longer.