 In the heart of every computer lies the true measure of its power, the CPU In previous Tech Tips we looked into the history of the microprocessor and in other Tech Tips we have also touched on processors in relation to building your own rig or in buying laptops. Now to bring it all home, we will take a look at, and de-geekify the particulars to processors as they stand today (late 2008). So, to do that, in this Tech Tip, we’ll take a general overview of the computer processor.
The Big Picture
The true worth, measure and power of a modern processor lies not just with its master clock speed, but really relies on a number of other factors as well. To understand processors, you really need to first start off with “the big picture” or an overview of the modern personal computer processor.
Let’s take a look at a few items:
Microprocessors are often called processors, main chip, integrated circuits, central processing unit or simply CPU (the initials for central processing unit).
 Cores refer to the actual number of processors built into a single die (the square of silicon that contains an integrated circuit). Older processors are referred to as single cores (one core) while newer processors can be dual core (two cores), triple core or even quad cores. Even higher multiple cores are in the very near future. The higher the number or cores, the better.
The core can also refer to the actual design of the circuit used for the particular processor. Often these are given nicknames when being developed, and these unofficially stick with the processor (for example, the original Pentium 4 processor used a “Willamette” core.) When released, these are then generally called the more familiar names we know: Pentium, Athlon, Core 2 Duo, etc. A processor can go through several “cores” before it is given a new name. For example, with the Pentium 4, there was the original Willamette core, but also the Northwood, Prescott, Cedar Mill and Gallatin cores. Older cores will not have the features built in that a newer, more modern  core would. For most non-Geeks, while this is interesting information, you don’t have to worry excessively about the core used if purchasing a new or recently refurbished personal computer. For you Geeks out there, well, we already know that you are not only obsessed with what particular core you are running, you could probably rattle off all the stats for the processor you have running at the drop of a hat!
A processor’s master clock rate is measured in Hertz (cycles per second). Older processors in Megahertz (MHz), and newer processors in Gigahertz (GHz). 1 Gigahertz is equal to 1000 Megahertz. What held true in the olden days, still holds true today - the higher the number, the better.
Cache is memory that can be quickly accessible, and dedicated to the processor. Modern processors build the cache into the die instead of having it in an external location. Cache is referred to by Levels, such as Level 1, Level 2, (abbreviated as L1, L2). Modern processors will usually have two levels of cache (though some can have 3 (L3)). When cache is often advertised, it is usually the Level 2 (L2) size that is advertised. The size of cache is measured in Bytes. Usually kilobytes (KB) or megabytes (MB). 1 Megabyte is equal to approximately 1000 Kilobytes (really, 1024 Kilobytes, but the numbers are usually rounded). The larger the size of the cache, the better.
The Bus Speed (also called the Front Side Bus speed or FSB speed) is basically how fast the processor “talks” to the main memory. This number is usually measured in Megahertz, but can also be measured in “MegaTransports per second (MT/s). More often than not, you’ll usually see this advertised in MHz for Intel processors. Note that AMD processors, because of their design, don’t really have a FSB speed, but rather a HyperTransport (HT) speed. The faster/higher this number, the better.
 OK, Now What?
This Tech Tip endeavored to give you a general overview of the processor at the heart of your Personal Computer, and things to look for if considering purchasing another computer. In future Tech Tips we will be looking at specific processor offering available for PCs. Long gone are the days when just the master clock speed of the processor was all you needed to look at to see if it was the right processor for you. Hopefully, you now see that there are other things to take into consideration, such as the number of cores, the cache size and even what core may be lurking inside the processor. These factors are truly what go into finding the true worth and the true speed of a modern processor.
Referenced older Tech Tips:
Microprocessor history parts 1-3:
http://www.geeks.com/techtips/2005/techtips-NOV22-05.htm
http://www.geeks.com/techtips/2005/techtips-DEC01-05.htm
http://www.geeks.com/techtips/2006/techtips-05JAN06.htm
Build your own PC:
http://www.geeks.com/techtips/2006/techtips-13july06.htm
Looking for Laptops:
http://www.geeks.com/techtips/2008/techtips-24AUG08.htm
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