CPU Basics

The Central Processing Unit (CPU) is often described as the 'brain' of the computer.  Perhaps describing it as the 'engine' may be more appropriate - it has no innate intelligence of its own, and more powerful CPUs cannot do more complex work; they simply work faster.

It is the job of the CPU to perform mathematical and logical calculations and also to decode instructions from programs running in the computer's memory.  The faster the CPU can do this work the faster the computer operates.  In fact, there are other computer components that may limit the speed of the computer, but the CPU speed is seen as a major indicator of computer performance.

The CPU is sometimes called the processor, central processor or micro processor.  It is rated by the number of bits that can be processed in a single instruction and the number of instructions that can be executed in one second.  Current CPUs are rated at 32 bits or 64 bits, and their clock speed could be anywhere between 1.5 GHz to 3.5 GHz.

One Gigahertz (GHz) is one billion cycles per second.  A 32-bit 2 GHz CPU can process 2 billion instructions per second, each with a maximum length of 32 bits.  32 bits in binary numbers is capable of expressing the decimal number 4,294,967,295.  Long story short -- a 32-bit 2 GHz processor is amazingly powerful.

Intel and AMD

The two major CPU manufacturers are Intel and AMD.  They have been competing with each other for years and often leapfrog each other in terms of technological advances.  The current leader seems to be AMD with its 64-bit Athlon processors, but the real world differences between top-of-the-line processors from Intel and AMD are usually very slight.

There are several factors that determine whether a particular CPU can be used with a motherboard.  The most important is the physical layout.  The motherboard has to be able to accept the pin design of the processor.  The pin design is often referred to as 'Socket x', such as Socket A, Socket 939, or Socket 478.  Motherboards are designed to accept a particular family of processors.

Another important factor to consider when choosing a CPU is the speed.  Motherboards have a maximum processing speed, so if you are trying to fit an older motherboard with a newer CPU, you might have problems.

Choosing a CPU

Deciding on which particular CPU to buy depends a lot on what you need it for.  Office applications like word processors and spreadsheets do not require a lot of computing power.  Games are among the most taxing of computer applications - often requiring the fastest and most powerful components available.

If you are an avid computer gamer set your sights on a CPU rated at 3 GHz or more.  Prices start at about $200 for a 32-bit processor all the way up to more than $1000 for the latest 64-bit processors.

If you have more modest computing needs, you can get by with a CPU in the 2 GHz range.  These are much more reasonable in price.  They start at about $70 for 32-bit processor and 64-bit processors are available at about $150.  Processors in this range are suitable for just about any computer application including graphics, video work and audio recording.

If you simply need a computer for word processing and using the Internet, consider getting a CPU in the 1 GHz to 2 GHz range.  These are the real bargains.  They can be had for less than $40 for a 32-bit 1 GHz processor and most processors in this range are less than $100.