In a computer system, the processor is like the brain. It performs all of the actions and everything that happens in the entire system is essentially managed by the processor. The processor runs the operating system, programs, and files. The biggest step in having a fast computer is having a good processor because every thing you do on your computer uses it.
Since the processor is probably the single most important component in your computer there is a lot of information you can learn about them. Since this is only a basics guide, we will only touch on the key topics that affect processors.
Clock Speed:
In the past processor manufacturers, computer makers, and sales people have misled the public to believe that you can measure the performance of a processor by its clock speed. You may be familiar with numbers such as a "2.8GHz processor". In this example 2.8GHz is the clock speed - it is the number of times per second that the processor ticks. Much like a clock ticks 60 times per minutes, a 2.8GHz processor ticks 2.8 billion times per second. Despite what you may think, having a higher clock speed does not translate directly to processor performance. Instead other things have a huge impact on performance such as Font Bus Speed, architecture, cache, and number of cores.
Front Bus Speed / Front Side Bus:
The processor talks with the RAM quite often, but RAM is not as fast as your processor. In order to communicate properly the two components must agree on a speed. The speed of communication between the processor and RAM is known as the Front Bus Speed or the Front Side Bus. The two names mean the same thing but are from two different brands.
Cache:
Many components in a computer system have a cache. Cache (pronounced: cash) is a small amount of high speed memory which can only be used by the device it is in. In the case of processor cache, it is an amount of memory available to the processor which helps the processor with computation and limits the amount of times the processor must communicate with much slower RAM.
32bit vs 64bit:
You may see that processors today come in both 32bit or 64bit versions. Some are even hybrids that can be either. In general you may not have to worry about this property unless you are interested in high end or specialty machines. In short, it depends a lot of the operating system you are using. In a 32bit system the internal instructions are 32 bits long and in a 64bit system they are 64 bits long. The most common difference noted by people is that a 32bit computer can only address 4 GB of RAM since in a 32 bit system, 2^32 is 4GB. Computers requiring large amounts of memory will need to use a 64bit setup.
Single Core / Dual Core / Quad Core / Multi Core:
You may ask exactly what is a multiple core processor. A processor with two cores (dual core) is the same as having two processors which are connected and are one physical chip. It allows for significantly better multitasking, and sometimes results in a single program using both cores for a much better experience. Some games, and applications such as photoshop are designed to use multiple cores. In general having more cores will result in a better experience.