What is Overclocking?

Overclocking means configuring a PC component (like the processor or the video card) to run faster than the component's default speed, which is set at the factory. PC enthusiasts (which is a fancy term for computer geeks) have been doing this at home for years. Although it was known that PC components could be sped up, finding the highest STABLE speed was a game of trial and error.

Companies like Intel and nVidia now make it much easier to achieve significant performance gains through overclocking. Let's look at an example. We overclock the graphics cards, memory, and motherboards of our PCs, but the most impressive gain comes from overclocking the processors (or CPUs). Here are some of the latest offerings from Intel's Core 2 Quad product line (some of which haven't been released yet):

Prices are from March 23rd, 2008

At first glance it seems that the fastest speed available would be 3.2 GHz at a cost of $1,500. Now the really interesting thing is, these are all essentially the same processor! The first four run at a slower speed than the QX9775 not because they are built differently, but because Intel crippled them at the factory. Intel knows it has many different markets to to sell its processors to, but building the same chip with artificial limitations is more cost-effective than making four completely different products.

Intel also knows that there is a rapidly growing interest in overclocking. They don't want to make it too easy to take a $266 chip and make it run as fast as the $1,500 model, so they struck a compromise.

The speed of a processor is a function of two values:

CPU Speed = ("Front Side Bus Speed") x ("CPU Multiplier)

Don't worry about what those terms actually mean just now.

To make overclockers happy, Intel allows us to change the Front Side Bus speed, which in turn allows us to increase (or decrease) the CPU speed. The multiplier, however, is off-limits to us. Higher multipliers make it easier to hit target speeds. As you can see above, the multiplier gets bigger as the chips get more expensive. Intel gets to sell its processors at different price points, allows overclockers to do our thing, and manages to give us incentives to spend more if we can.

The bottom line is, overclocking can make a $266 chip outperform an unmodified $1,500 one. Now you might have noticed from our chart that Intel lets you change the CPU multiplier on the QX9775, but it costs a grand-and-a-half. So while there are ways of building even faster PCs, our focus remains on one concept: giving you unbelievable speed at an affordable price!