The Central Processing Unit - known otherwise as the CPU - is the nerve center of a computer. As the name suggests, the CPU processes information in a computer in the form of binary (0's and 1's) and converts it into instructions that tell the computer what to do. The CPU handles most of the everyday operations of a computer.

It is not necessary to understand the exact nature of the way a processor operates, but there are a great deal of terms and facts that are important for anybody who wishes to know more about computer architecture. The CPU is a physical computer component and is not typically directly attached to the system board (formerly known as motherboard).

The thing people care most about when learning about any computer component is not about how it works or how it fits in respect to other things, but rather, about how fast it is. This is especially true for CPUs, where the higher the speed, the better the chip. Of course, this isn't necessarily true of all processors - especially across brands - but speed is probably the most important number to understand. Speed is measured in Hertz, abbreviated Hz, and represents the number of operations the processor can perform in one second. Modern computers are measured in Megahertz (MHz) or Gigahertz (GHz).

The speed of the processor equates directly to the amount of data that it can process at once. Despite this, however, two brands or different types of processors should not always be compared directly. Intel and AMD chips achieve different performances per Ghz, as do Pentium 3s and Pentium 4s, due to various other factors regarding the exact architecture of these chips. These numbers should be used to compare processor speed to like processors.

Despite how powerful a CPU can be, it is interesting to note that it can only perform one task at any one time. In order to allow a processor to run multiple programs at once, it utilizes a method known as "cooperative multitasking" (or multitasking, for short). A processor achieves the illusion of running multiple tasks at once by switching from one task to another at a given interval. It is because of the inability to execute multiple things simultaneously that computer become slower when there are a lot of programs open at once.

In this case, it is important to understand parallel processing. Parallel processing involves using more than one CPU to be able to process multiple things at once. As clock speeds have reached their physical limitations at 4 GHz, parallel processing has become the best way to alleviate this problem. Many of Intel's Pentium 4 chips have utilized a method of processing multiple pieces of information at once called hyperthreading. While it does not involve the use of a second processor, this method allows two processes to occur side-by-side. The exact details of how hyperthreading works are not important, but it is important to know that this method is not nearly as efficient or effective as using a second physical unit.

While dual-processor systems have existed in the server and workstation markets for years, there have been no such things for PCs. This is because any such solution would be expensive and require extra cooling, making systems much louder. Recently, Intel and AMD have designed what is known as a dual-core processor. These effectively allow two processors to coexist on one single piece of silicon. They are more efficient and run cooler than two separate processors. However, it is important to understand that these processors can run hotter than single-core processors and will need adequate cooling to prevent potential damage to vital components.

In addition to allowing multiple programs to run at one time, parallel processing can speed up a single program by allowing multiple pieces of it to execute concurrently. However, in order for this to occur, it is necessary for the program to be built in order to utilize this ability, which few programs are able to do. Because of this, running a single application at a time is not as efficient on a dual-core/processor machine as it would be with a single processing core.

For anybody who wishes to delve deeper into the field of computer architecture, it is important for them to understand processor compatibilities. As the illustrations show, a typical processor contains a series of metallic pins that, when inserted into the socket on a motherboard, will come in contact with a series of circuits. The designated names normally refer to the number of pins that the socket contains. There are a great number of types of sockets that computers use, and these sockets are not interchangeable. A processor made for one socket will not fit in another, and most sockets will only accept specific processors.

Cache refers to a type of short-term memory used by the processor, and is also sometimes known as static RAM, or SRAM. Cache is temporary memory that is used by the processor as it performs calculations. It is faster than traditional computer memory and is contained directly on the processor, but is much more expensive and, therefore, comes in smaller amounts. Due to its speed, the more cache a processor has, the faster it can run, as it will need to access memory less in calculations. However, this performance gain is often negligible. CPU cache comes in several levels of cache: Level 1 (L1), level 2 (L2), and sometime level 3 (L3). Level 1 cache is the fastest, but most expensive, and is the smallest of cache. Because of the expense of level 1 cache, CPUs include a level 2 cache, which is slower but significantly cheaper to manufacture than level 1 cache. Some CPUs even include a level 3 cache, which is even cheaper than level 2 cache, but is slower and comes in larger quantities.