The ability to select a specific core voltage for the CPU could be the factor that determines overclocking success or failure. Many performance motherboards will offer a full selection of core voltages, most likely through the system BIOS, but also through on-board jumpers. Other motherboards do allow voltage increases, but only using a set percentage boost such as 5% or 10%. This is standard operating procedure on many VIA motherboards, but may also be found with other chipsets as well. There are also motherboards that simply use a “CPU Detect” format that limits the core voltage to the default level of the CPU.
Other than extremely old Intel CPUs, the clock multiplier can only be adjusted on AMD processors. The multiplier can be changed using select AMD Thunderbird/Duron motherboards or with an Athlon Goldfinger overclocking device. This useful feature allows the default CPU multiplier to be overridden and is one of the best methods of getting the highest core speed from an AMD Athlon, Duron or Thunderbird processors.
When trying a particularly difficult overclock, sometimes the system may halt and refuse to start up. This is especially true when using the FSB selections in the system BIOS. Look in the motherboard manual for any reference to resetting an overclocked PC and write it down for future reference. Usually this safety feature will consist of a keyboard button being depressed while the system boots.