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What is overclocking your CPU all about?

This guide briefly touches on what CPU overclocking is, what the benefits are and some of the potential risks, if you have heard overclocking being mentioned but never quite understood what it was then this is a great place to start your research

What is Overclocking?

Many people probably don't know what overclocking is but have possibly heard the term used before. To put it in its simplest terms, overclocking is taking a computer component such as a processor and running at a specification higher than rated by the manufacturer. Every part produced by companies such as Intel and AMD are rated for specific speeds. They have tested the capabilities of the part and certified it for that given speed. Of course, most parts are underrated for increased reliability. Overclocking a part simply takes advantage of the unused potential already present within the specified parts

What are the benefits?

The primary benefit of overclocking is additional computer performance without the need to select a more expensive processor. Most individuals who overclock their system either want to try and produce the fastest desktop system possible or to extend their computer power on a limited budget. In some cases, with the right hardware and know-how it is possible to boost system performance by 50% or more!

How does overclocking work?
There are differences in overclocking each processor, processor series and there are differences between Intel & AMD yet the principles remain largely the same. To overclock settings are changed in the computers BIOS that result in the processor running at a higher speed.

There are three main settings that are changed to achieve an overclock in one of our systems or bundles:

FSB (Front Side Bus): The data bus that carries information from the processor to the main memory and the rest of the system. An internal multiplier determines the speed of the processor in MHz or GHz by multiplying the FSB speed of the system.
Multiplier: The ratio of a given processor's speed (in MHz or GHz) as compared to the FSB (Frontside Bus) speed of the PC it is installed in. A processor with an internal multiplier of 20x installed in a system with a FSB of 200MHz would run at 4.00GHz, since 20 x 200MHz = 4000MHz.
Memory Divider: Most modern motherboards allow a memory divider to be set. This divider allows the system memory to run slower than the actual FSB speed. By default, FSB speed and memory are usually set to a 1:1 ratio, meaning that increasing FSB speed (by overclocking) increases memory speed by the same amount often making the system unstable at higher speeds without the divider.

By increasing the FSB and selecting a lower memory divider it is often possible to greatly increase the performance of the components.

For example a PC with a processor running at 20 x 133MHz is running at a clock speed of 2.66GHz. When the setting is changed to 20 x 200MHz the processor speed will be increased by 1.33GHz. That results in a 50% overclock and a new processor speed of 4.00GHz! This will result in an increase of memory speed so a divider will have to be selected to ensure system stability.
For the components to run stable a complex set of voltages must be tweaked to provide the right power to run at the higher speeds. A performance cooler is always recommended to deal with the excess heat and always supplied when required on one of our systems or bundles.

Are there any risks?

As long as the components have been carefully selected, the settings expertly chosen and the cooling and power supply are able to cope with the excess stress there is only performance to gain from overclocking. With intensive stability testing it is possible to ensure system stability equal to that of a non-overclocked system.

The faster a computer goes, the more heat it produces. This is especially true when the voltage being fed to certain components is increased. Excess heat in the processor, motherboard chipset or memory can cause crashes and system instability so an upgraded processor cooler and well ventilated case is essential.

Overclocking a PC also increases the amount of power it draws, and this may lead to system instability if its old 300W power supply is not up to the task and may lead to spontaneous reboots. If you are running a modern high end overclocked system expect to need a quality branded 450W power supply or more. The brands to look for are Corsair, Coolermaster and Antec with all having excellent reputations and proven reliability. All of our overclocked full systems are provided with a high quality power supply for this reason.