Computers as Components, 3rd Edition

3.7 CPU Power Consumption

Power consumption is, in some situations, as important as execution time. In this section we study the characteristics of CPUs that influence power consumption and mechanisms provided by CPUs to control how much power they consume.

Energy vs. power

First, we need to distinguish between energy and power. Power is, of course, energy consumption per unit time. Heat generation depends on power consumption. Battery life, on the other hand, most directly depends on energy consumption. Generally, we will use the term power as shorthand for energy and power consumption, distinguishing between them only when necessary.

CMOS power characteristics

The high-level power consumption characteristics of CPUs and other system components ...