CPU Overclocking Basics

Overclocking means clocking a hardware part at a frequency higher than the default one. You don’t have to know why overclocking is possible at all. It may be due to a high margin of safety provided by the manufacturer, due to marketing reasons that made the manufacturer set lower default characteristics than possible, or due to the use of faster components than necessary. Whatever the reason, your task is to make good use of the offered opportunity.

In a PC, everything is standardized and synchronized. The standardization is obligatory for components from different makers to be able to work together at all. The synchronization ensures that the components work together smoothly. The frequency of the system bus (or Front Side Bus – FSB) is considered the basic frequency of the system. The rest of the buses the various devices and components are connected with usually work at lower frequencies that are generated from the FSB frequency by means of divisors. The CPU frequency is currently much higher than the FSB frequency and is generated by means of a multiplier.

For example, the Intel Core 2 Duo E6300 processor works at a bus frequency of 266MHz. Its frequency multiplier is x7 and the multiplication of the two yields the resulting CPU frequency, which is 266x7=1.86GHz. It means that the CPU frequency can be increased by increasing the FSB frequency or the multiplier.

Senior models of modern CPUs have an unlocked frequency multiplier and permit to increase it, but such CPUs are too expensive in comparison with junior models from the same family. It is not reasonable to buy one because overclocking can lift the performance of the junior models up to the level of the senior ones and even higher.

Thus, CPU overclocking usually boils down to increasing the FSB frequency. Taking the same Intel Core 2 Duo E6300 as an example, if you increase its FSB frequency from the default 266MHz to 400MHz, the CPU frequency will grow up to 2.8MHz, by 1000MHz almost. If the FSB frequency is increased to 500MHz, the CPU will be clocked at 3.5GHz, etc. This is in fact all the information you need to go into your mainboard’s BIOS Setup, increase the FSB frequency and overclock your CPU, but there are some things you should be aware of yet. You’ll learn more of them eventually, and some of them are unknown even to me because new CPU models have peculiarities of their own. But again, there are basic things you can rely upon in all your overclocking attempts.