This, x100. Most people would know of overclocking but not undervolting, with the irony being that the latter can be far more useful for the average user.

For example, I have a stock air cooled Nvidia GPU. Standard overclocking doesn't get me much because I get temp throttled. However undervolting, i.e., you boost clocks at lower voltages while not at higher voltages, leads to higher sustained clocks with _similar_ power/temps.

This is a consequence of power generally being linearly related to frequency and super linearly (even quadratically) to voltage.