Many people consider the CPU (Central Processing Unit) to be the brains of the computer. This analogy is very loose because, for the most part, the CPU cannot keep data stored inside it like a brain. In contrast, it is used to process much of the information needed by the computer, just like our brain thinks and processes information and gives orders to our other body parts.

 Intel's Next generation processor, the Itanium, featuring 64-bit architecture.
© 2001 by Intel Corp.

Over the past few years, we have seen the CPU MHz speeds go from 100 MHz to over 2 GHz (1000 MHz = 1 GHz). This is one reason that people need to learn about a CPU. Many people would expect a 1.8 GHz Intel Pentium 4 to be much faster than a 1.4 GHz AMD Athlon because its speed is 0.4 GHz faster. In truth, not only is the Intel Pentium 4 up to three times more expensive than the AMD Athlon, it is either much slower or neck to neck in most "Real world tests", which compares the amount of times that it takes each CPU to perform a certain task.

With this information, you know that you should not judge a computer by the "speed ratings". But if one CPU goes at a faster MHz rate and is slower, what does determine the speed of the CPU? There are a variety of factors, but we will show you the main parts of a CPU, and what they are used for.