Active power

 CPU power consists of logic power and io power. Logic power consists of dynamic power and leakage power. Dynamic power included the power used by the clocks and the power used for computation.  Dynamic power varies according to the workload. For example a simple application not using floating point calculation will consume less power as the floating point unit is unused. Leakage of power exists when  transistor are charged and discharged  

Io power is used to drive the connections from the CPU to the peripheral. Some io connection uses power proportional to the bandwidth (eg ram). Some io uses constant power all the time eg PCI. 

The third type of power is called platform power which is the power used by ram, disk, network card etc.