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The current generation of CPU's is pretty powerfull, but you will have to agree that there is no such thing as "enough power" when talking about CPU's. I guess speed grows on you, you get used to it pretty quick ... So, we want faster CPU's.... unfortunally these come not cheap. A really fast CPU can cost you over a $1000, which is a lot of money to me.... So we have to find a diferent solution in getting more performance. We're about to make the CPU work it bit more ... Warning: Overclocking may harm your CPU, hardware and even wreck the data stored on your harddrive, so please read the disclaimer!

Overclocking basics

Let's start with the fact that CPU's are build in large batches. None of the manufacturers will test all of these CPU's individually, they will take a sample and see if it meets the specifications set. For example a 900 Mhz CPU batch. The samples perform poorly and can only be sold as a 600 Mhz CPU.

Another reason to sell a 900 Mhz CPU for a 600 Mhz CPU can also be due to the lack of available 600 Mhz CPU's.

Just relabeling the CPU's won't be sufficient. The need to be locked, otherwise why buy a $1900 CPU when a $150 CPU does the same job ?

So the manufacturers lock the CPU with a hardware locking mechanism. We need to hack that locking mechanism which is NOT the same for each CPU type.

How is the frequency set ?

For most CPU's (specifically in the Intel class CPU's, where we find AMD, Cyrix, etc also) frequency is set as follows:

Base clock (=FSB) * multiplier

This way a 600 Mhz is set as: 100 Mhz * 6 = 600 Mhz.

So there are 2 variables setting the final frequency, the Front Side Bus clock and the Multiplier. Changing either one of them results in a different frequency:

multiplier of 6 set to 7: 100 Mhz * 7 = 700 Mhz

or:

base clock of 100 Mhz to 110 Mhz: 110 Mhz * 6 = 660 Mhz

There are basically 2 base clocks: 66 Mhz (Intel for example) and 100 Mhz (faster Intels and AMD for example). 133 Mhz and others are out there too.

Voltage

This is not the only thing to set. More performance requires more "energy", therefor we might be forced to increase the CPU Voltage.

There is one downside to increasing voltage: heat. The higher the voltage, the higher the heat produced and therefor cooling must be improved.

Conclusion

In this very brief intro we see that overclocking is possible. However very specific for each CPU type, that's why I wrote down my own experiences for WeetHet, two examples:

• SocketA - AMD Athlon/Duron 600 Mhz to 900 Mhz
• SlotA - AMD Athlon 500 Mhz to 700 Mhz