CPU
(Central Processing Unit)
The Engine Room
The Processor is the brain of the computer. Information is collected from your disks, stored temporarily in RAM, and the CPU uses it to do the calculations required to run your programs and to read your data. All modern processors will do this adequately for most general computing purposes.
In the picture on the right the pale blue part is the CPU. Most of what you can see, the dark blue part, is the cooling fan. The fan is vital. Lose cooling for an instant and your CPU is cooked — dog tucker.
CPU Speed
Current newer PC CPUs range from 2500MHz processor speed up to 4200MHz and they're increasing as we speak. Just to confuse matters, using standard scientific notation, they’re starting to be referred to in GHz instead of MHz. 1000MHz = 1GHz. The bigger the number, the faster the processing, and the more quickly it will do the sums.
Until fairly recently, processor speed was easy to understand. the bigger the number, the better the CPU. Now the situation is less clear cut. Complications in CPU architecture mean that processor speed is no longer a reliable method of comparing CPUs. You must take into consideration 32 vs 64 bits, dual cores, and cache sizes and levels.
The Good News
For most people using this site, any currently available new CPU will do the job. You only need to splash out for an expensive, top of the range CPU if you have very demanding video or 3D graphics programs or games. Or if you need to have a "server" hosting websites or to work with very large databases. Extra RAM is far more important for users who are doing what most of us do.
The range of processor types and speeds is confusing. My rule of thumb for those using their PC to carry out ordinary tasks is to buy a PC with the best processor available one to two years ago. Prices of those CPUs tend to fall dramatically.
It's not easy to keep the subject of CPUs under control. It's complicated. The aim of this website is to present easily understood information for non-geeks, so I'm just going to explain the basics. If you wish to study the subject in more depth, have a look here: PC World: CPUs Buying Guide.
AMD/Intel
AMD
processors generally have been a little cheaper than their Intel equivalents,
mainly because AMD are the number 2 manufacturer. There’s nothing wrong
with the product.
Intel and AMD use different ways of numbering their processors, so that
(for instance) a 2000MHz (2GHz) AMD is about the same as a 1600Mz (1.6GHz)
Intel. This nomenclature may change in the near future.
All else being equal.
Celeron, Sempron & Duron
The Intel Celeron processor and the AMD Sempron, are the budget equivalent of the Intel Pentium and the AMD Athlon respectively. They have less “cache”. That's a small amount of super fast memory built into the processor. Without going into detail, that means that your programs are slower to respond than they would be with the fully featured CPU. The difference would be negligible in normal tasks but very significant in some more demanding work - for instance, working with very large databases.
If you come across an AMD Duron, that's an older equivalent of the Sempron.
If you are only going to be writing letters and surfing the Internet it probably wouldn't make a noticeable difference. But you don't know what you might be demanding of your PC a year from now. A year ago I didn't envisage publishing a web site.
64 bit Processors
Until
mid 2006 the top end AMD X64 CPUs were the best performing chips available.
Top of that range is the 2.8GHz Athlon 64 FX-62.
A 64 bit processor has twice the number of "pathways" to channel data through as a 32 bit. This does not translate to a mere doubling of data capacity. The way computers process digital data using binary notation, we're comparing 264 with 232. So there is a (so far largely unrealised) potential for an enormous increase in data traffic.
If you're a standard (32 bit) Windows user, be aware that, at the moment, a 64 bit version of Windows XP is not released in final form and that you may not be able to obtain drivers for your particular hardware: your printer for instance, or your graphics display card.
Until such time as 64 bit versions of Windows and the programs you use are published, some of the potential of 64bit CPUs remains unrealised.
I have an Asus laptop with an AMD Turion 64 bit CPU. I have a pre-release copy of Windows XP 64 but can't use it because the video drivers are not available. Frustrating.
However, if you do have the software you can still use all 32 bit programs with 64 bit chips, including Windows XP.
An exception, which won't affect very many readers, is the Linux operating system. I run both Windows XP and Ubuntu Linux 64 bit on my laptop. Linux unpaid programmers have produced drivers for my hardware that the makers can't or won't provide for Windows.
Dual Core CPUs
These are two processors built into one microchip.
Intel Core Duo
In the latter half of 2006 Intel took back the performance lead with the Core 2 Duo - formerly called the Conroe.
These CPUs range from moderately expensive 1.86GHz E6300, right up to the astronomically expensive 2.93GHz X6800.
AMD Athlon 64 X2
Until very recently, these were the dual core performance champions.
Watch this space.
CPUs and Motherboards
If you are going to be adventurous and build your own PC or upgrade to a faster CPU. Please note that different CPUs require different socket types and motherboard chipsets. You need to do your homework to ensure that the new CPU is compatible with the motherboard it's going into.
