When overclocking a computer, the processor, system memory and motherboard all have a different and important part to play in the process. The abilities and overclockability of each component has a significant effect on how successful the whole experiment will be. Let's take a closer look at each component:

The Processor (CPU): As readers might know, two important variables govern how fast a modern processor goes. Its internal multiplier and the FSB (Front Side Bus) setting of the motherboard and memory. The FSB is the effective speed of data transfer between the processor and the main memory (it's also the base speed that the system's memory runs at), while the multiplier is an internal indicator of the speed of the processor.

A processor's speed equals its multiplier (x) the FSB in MHz. Therefore, an Intel processor with a multiplier of 16 working with a FSB speed of 200MHz would run at 3.2GHz. There are two ways a processor can be made to run faster; increasing the multiplier, or increasing FSB speed.

Many modern processors have 'multiplier locks' which prevent users from changing the internal multiplier settings partially or completely, so increasing FSB speed tends to be the most common and effective method of overclocking.

The Memory: A system's main memory speed determines the speed of data transfer between the processor, memory and the rest of the system. As you can imagine, this is the most important variable for computing performance in some systems. In all modern Intel and AMD systems, the FSB speed is directly linked to the speed of the memory by default, so the faster the memory is clocked, the faster the processor goes, since processor speed = (internal multiplier (x) FSB speed). This can be changed, but the 1:1 ratio between FSB and memory speed is the most desirable for overclocking.

AMD Athlon 64 systems do things a bit differently, since the memory controller is part of the CPU itself, so there is no conventional FSB carrying data from the processor to the rest of the system. Overclocking the memory still works essentially the same way, though the technology/terminology has changed. More on this in our AMD overclocking section below.

The Motherboard: Just as the motherboard is the heart of every computer system, it is also central to your overclocking efforts. The motherboard's circuitry connects the processor and memory together and its BIOS options determine in what ways and by how much they can be overclocked. Even the highest quality memory and most overclockable processor can accomplish nothing if placed in a motherboard with no or limited overclocking options in its BIOS, or a board equipped with a new, poorly implemented or unstable core logic chipset.

Again, each component above depends on the other two when it comes to overclocking.

Hardware considerations for overclocking: Heat and cooling

The faster a computer goes, the more heat it produces. This is especially true when the voltage being fed to certain components is increased, a standard overclocking method. Excess heat in the processor, motherboard chipset or memory can cause crashes and system instability, and may be one of the limiting factors in determining the maximum overclock for a system.

The stock heatsinks included with most processors are perfectly adequate for cooling them at their stock speeds, but may not handle the additional heat generated by overclocking very well, especially if the computer chassis is not suitably ventilated. Readers may be better off investing in one of the many custom cooling solutions on the market, or at least buying some case fans to ensure an adequate flow of fresh air through their case. Take a look here for some cooling ideas. The same goes for the chipset and to a limited degree, the memory.