The Voltage Selection for Thunderbird and Duron
All die-hard overclockers know it. The key to a successful overclocking is choosing the right core voltage. This is valid for Thunderbird and Duron just as much. While Thunderbird has a default voltage of 1.7 V, Duron is using 1.5 V. If you want to overclock the two processors successfully, you need to raise the voltage.
I don't really think that there is much sense in providing the information on which CPU-pins are responsible for the core voltage, because most motherboards will most likely give you an option to change the voltage either in the BIOS or via jumpers. However, you should be aware of one important limitation.
As you can see, the maximal voltage that can be chosen is 1.85 V. Please realize that when you are trying your luck with Thunderbird or Duron. Thunderbird can only be supplied with a core voltage of 0.15 V above its spec (which is less than a 10% raise), unless you want to change the whole motherboard power supply circuits. Duron is better off. You can add some 0.35 V to the 1.5 V default voltage, which should be good enough for most reasonable clock speeds.