what is overclocking
Most devices in today's computer
run in synchronous mode. Means that there is a clock to tell
the devices to act. Overclocking means to manipulate this clock. There are different clocks but
in some way they interact all.
Most of these clocks are specified
to a typical rate (e.g. PCI 33MHz). Raising this rate means
overclocking. Manufacturers test their components to comply with these specified clock rates.
To ensure they run at every circumstance (guaranteed environment) an additional tolerance is
necessary. This is the starting point for overclocking.
changing bus speed
changing clock multiplier
changing CPU voltage
changing RAM settings
changing AGP-to-PCI rate
The tempting idea behind overclocking is to increase system performance at very little cost. In many cases you only need to change a few settings on your motherboard to make your system run faster. In other cases you only have to add a few components (usually for cooling) to achieve the performance increase.
In the past, overclocking was usually nothing more than increasing a CPU's clock speed to that of the next higher model, e.g. a Pentium 120 to a Pentium 133. Now, with new bus speeds available on several motherboards, you can change the clock and bus speed of a CPU to values that don't officially exist. This new way of overclocking is yielding an even higher performance increase than the classic one. It even gives you the ability to increase the performance of the fastest model of a particular CPU production line (e.g. P200 to 250 MHz, PPro 200 to 233 Mhz).