Terms and Definitions
Before we begin, we'll cover some of the commonly used terms used in the guide and some general definitions. After all, I have found that most enthusiasts are like me when it comes to playing, they not only want to know how to make it work, they also want to know WHY.
Chipset - A chipset is defined as "a group of microchips designed to work as a unit in performing one or more related functions." As a general rule, today's chipsets consist of two parts, a Northbridge and a Southbridge. Both of these terms will be discussed later, but the two working in tandem creates a better and more efficient flow of data with fewer conflicts. Common chipsets used with the Athlon XP processor at the time of this writing include the VIA KT266A, KT333 and KT400 as well as the nVidia nForce and nForce2. SiS has one or two chipsets designed for the AMD line, but they are non-players for the most part in terms of overclocking potential.
Clock Multiplier - This term will be getting a workout in this guide. The Clock Multiplier is an internal setting of the processor that is used to determine the processor speed. As an example, if you have a processor that is set at the factory with a clock multiplier of 10 and a native FSB (see below) of 100MHz, then the resulting processor speed is 1000MHz or 1GHz. Since it is a simple matter of multiplication, the name becomes a no-brainer.
Double Data Rate (DDR) - Double Data Rate, or DDR as it is commonly called, is becoming a very popular concept with the computer industry lately. With speeds gaining ever higher levels of performance, there had to be a limit somewhere. So when that limit was hit, what were the manufacturer's to do? Why, they created DDR. What this does is to allow for the support of data transfers on both edges of each clock cycle (the rising and falling edges), effectively doubling the memory chip's data throughput. And even better is that all of the motherboards and the Athlon processors themselves support this feature natively. So not only can we double the effectiveness of our memory, but we can also double the speed at which data flows between areas of the motherboard too.
Front Side Bus (FSB) - In simple terms, the Front Side Bus (FSB) is the data path and physical interface between the processor and the main memory. When used from an overclocker's standpoint it is generally referred to as a speed measured in Megahertz (MHz). The higher the number, the faster the data flows.
Northbridge - "The Northbridge is the portion of the chipset that communicates with the computer processor and controls interaction with memory, the Peripheral Component Interconnect (PCI) bus, Level 2 cache, and all Accelerated Graphics Port (AGP) activities. The Northbridge communicates with the processor using the Front Side Bus (FSB)."
Southbridge - "The Southbridge is the portion of the chipset that manages the basic forms of input/output (I/O) such as Universal Serial Bus (USB), serial, audio, Integrated Drive Electronics (IDE), and Industry Standard Architecture (ISA) I/O in a computer. Unlike the Northbridge, the Southbridge moves data by means of the Northbridge's PCI bus."
VAGP - VAGP refers to the voltage setting of the AGP port on the motherboard. Not all motherboards allow for the adjustment of this setting, but for those that do allow for it, the benefits can be great.
VCore - This is the voltage setting for the processor. This is where you can force your speeds to the next level, or completely fry your precious CPU.
VDIMM - As the name suggests, this is where you set the voltage levels of your memory modules. Though higher voltages can help you achieve better overall speeds, they can also cause some system instabilities.
Quoted definitions above were found at whatis.com.