What is a CPU?

This is a beginners guide to CPU's. Please use the articles menu if you require more in depth articles. The CPU is often called the main processor of your PC. CPU stands for Central Processing Unit. When you are buying a PC from a high street store the main selling feature is always the speed of the CPU. You will notice it will say 2.4Ghz or 3Ghz PC. The truth is that the CPU is set at these speeds and has no relevance on what else you could have inside your PC. While the CPU is undoubtedly one of the most important if not the most important piece of the PC is it no use working above its class. Watch out for PC's with a very highly rated CPU and substandard parts around it because the overall performance will suffer badly. The saying that a machine will be as fast as its slowest component is especially true when it comes to computing. One slower or substandard component will create a bottleneck that slows down your entire PC.

What does the CPU look like?

The CPU will likely be the larger of the chips on the mainboard inside your PC. If you have bought the PC from new the CPU will be covered by a heatsink and fan. The heatsink and fan are extremely important. Without these the CPU would get too hot to work and possibly melt or burn out. Be very careful to replace the fan correctly if you remove it to have a look at your CPU. Its also worth upgrading your fan from the stock fan that comes with the CPU because this will allow your CPU to work more efficiently and allow for potential overclocking should you wish to try that.

What does the CPU do? 

The CPU is the main processor of your PC. Everything that goes on in your PC at some point goes through your CPU. In reference to the human body the CPU is brain of the PC. It is artificial thinking but the CPU is where all the logic is applied. As a very basic example computer code is basically mathematics. if you wanted to calculate 2+7 you would need an input an output and a processor to add the logic. The logic in this case is simple addition. You would input 2+7 on a keyboard. This would be registered and sent to the CPU for analysis. The CPU would see that the addition logic is required and use this inbuilt logic to send the answer of 9. That of course is a simple instruction but the idea for all processors is the same. Input > Apply Logic > Output. this of course is being done millions of times per second allowing for very complicated mathematics to be done in fractions of a second.

How do you measure the speed of a CPU?

The CPU's speed is a measure of MHz (megahertz) or more recently GHz (gigahertz). a chip with a megahertz rating of 900Mhz would be able to complete 900Million cycles every second. However don't be fully deceived by this figure alone. This figure only shows how many clock cycles the CPU can do in a second. How much being done in each cycle is another matter. I urge you to check out some benchmarks on CPU's before you you decide that the one with a faster rating has the best performance. Unfortunately the need for speed and higher clock rating have driven the CPU industry to work on this factor without really seeing what the performance of these chips are like.

Since CPU's have started to top out at fast speeds now, the major manufacturers are looking for ways to increase the processing power without increasing the actual speed of the CPU. The route they have taken with this problem is with multi-core CPU's. On a single chip these new processors have 2, 3, 4, or even more processing cores fitting. These cores share the workload and process faster than traditional CPU's even though they are not rated at higher speeds. So remember don't just look at the rated speed as now more than ever this doesn't give you the full story. Multi-core CPU's however can only be more efficient if the software is capable of utilizing all the available cores otherwise the extra cores are made redundant.