Just as a brain needs to rest and relax, computers will also need that from time to time but they can operate longer times than the average brain. While the brain sleeps, the computer can carry on with its duties of processing data and converting them to knowledge and information.
Summing up, although the CPU is sometimes called the brain of the computer, it is actually a misnomer because as I have outlined in this article, the brain is definitely different from the computer in varying ways and the brain has yet to teach the computer to behave 100% like a brain.