• Version.
• Overview.
• Disclaimer.
• How overclocking works.
• Precautions.
• Factors affecting overclocking.
• Tools needed for overclocking.
• Overclocking.
• Tips and tricks.
• Conclusion.

1.0 Friday, February 18th, 2000

The first question everyone asks is, what is overclocking? Overclocking is when you modify a processor’s settings to exceed the recommended manufacturer’s speed. 

For example you may purchase a 450mhz processor and overclock it to 500mhz or more. You may be wondering how safe and how complicated it is to overclock a CPU. Hopefully you will have some answers before this article concludes. I will assume that you know very little about overclocking and so experts may wish to skip to the section on to tips and tricks.

The reason why one would overclock a system is because you can drastically increase your overall performance for little or no money.

How overclocking works.   (INDEX)
The PC system speed works on a multiplier system and FSB (front-side bus) relationship that ultimately determines how fast the system should run. Let’s take a look at some terminology before we get started:

• AGP bus: Advanced Graphics Port.
   
• BIOS: Static RAM storage medium that contains the hardware configuration of the system.
   
• Front-Side Bus (FSB): The data path speed between your CPU, motherboard chipset and main memory.
   
• Motherboard: Main system board that houses the CPU, RAM and I/O devices.

The easiest method for drawing a picture on how overclocking works is by setting an example: Let’s take a look at how a Pentium II 450mhz communicates with the main memory and how the multiplier works in this case. 

The Pentium II 450 consists of a 450mhz-core processor speed and requires a 100mhz front-side bus speed to operate under Intel’s recommended settings.

All processors operate via a multiplier system that can readily be determined by dividing the processor core speed, by the (FSB) front-side bus speed. In the Pentium II 450mhz example we arrive a multiplier of 4.5 Mathematically speaking:

(CPU Core speed / Front-Side Bus Speed) = Multiplier.
or
(Front-Side Bus Speed x Multiplier) = CPU Core Speed.

And of course in our example:

(450mhz/100mhz) = 4.5 multiplier.
or
(100mhz x 4.5 multiplier) = 450mhz.

A couple of other examples: A 600mhz Pentium III CPU runs at 6 multiplier (100mhz FSB x 6) = 600mhz and a 650mhz Pentium III CPU runs at 6.5 multiplier (100mhz FSB x 6.5). A case with the Intel Celeron CPU is a little different since the FSB is clocked at 66mhz only and this means a 500mhz Celeron is 7.56 multiplier. The newer Pentium III processors have a 133mhz FSB which means a newer Pentium III 750 with a 133mhz FSB has a multiplier of (750mhz core /133mhz FSB)= 5.6.

What does this have to do with overclocking? Plenty! For example our 450mhz CPU with a multiplier of 4.5 can be overclocked two ways: First you can increase the multiplier from 4.5 to 5.0 which would overclock the chip from 450mhz (100x4.5) to 500mhz (100x5), secondly you can increase the FSB speed to 110mhz which would give you (4.5x110) to 495mhz.

Today, Intel has gotten wind of these two overclocking tricks and has implemented "multiplier locks" to their CPU’s which means a 450mhz chips is multiplier locked at 4.5, a 500mhz chip is multiplier locked at 5 and so on. If you try to change the "hard-coded" multiplier setting on a "multiplier locked" CPU your system will most likely not even boot. This does not prevent overclocking but does make it a little trickier as the only option remaining to overclock a system is via increasing the FSB speed. The tricks of the trade here are a very flexible motherboard that allows faster FSB settings and CPU with a low multiplier.

In most cases overclocking can be achieved easily by increasing the Front-Side Bus speed (FSB) and some other minor tricks. We will examine those tricks later.

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