"A computer like this can execute approximately 100 million instructions per second. Your particular machine might be twice that fast or half that fast, but that's the ballpark."
"Your brain, on the other hand, can understand any number of speakers. It needs no training and will make zero mistakes. It may even be able to understand multiple languages! And the speech processing portion of your brain is just one small part of the whole package -- your brain can also process complex visual images, control your entire body, understand conceptual problems and create new ideas. Your brain is made up of about one trillion cells with 100 trillion connections between those cells. We might take a rough estimate and say it is handling 10 quadrillion instructions per second, but it really is hard to say."
I'm going to go with a brain as a computer.