Serial and parallel processing

The brain is not slow nor imprecise in performing calculations.

For example, a professional tennis player can follow the trajectory of a tennis ball after it is served at speed as high as 160 miles per hour, move to the best spot, position his arm, and swing the racket to return the ball within a few hundred milliseconds. It can accomplish all these tasks with power consumption about tenfold less than a personal computer.

This is all possible because the brain employs serial and parallel processing, while computer tasks are mainly performed in serial steps.