On larger machines the CPU requires one or more circuit boards however on smaller machines like laptops it is housed in a single silicon chip called a microprocessor.
The Clocking Rate
A little bit of History...
The first commercially sold microprocessor was the Intel 4004 produced in 1971, the 4004 was very good but for its time it was an amazing new discovery in the world of computing. However Intel did not create the CPU as it was created by a man named Frederico Faggin who created the idea and made it first however he did not sell it commercially and Intel sold their one before. Compared to the CPU below the 'Intel Core i7' which is the best CPU you can buy in the moment it isn't very good but many of the best inventions have humble beginnings.