A multiplier is already flashed inside processors: for example, if the frequency of your processor kernel is 650 MHz, this multiplier is equal to 6,5 for the standard bus frequency. Any attempt to modify a multiplier may lead to the processor failure. The only way out of this situation is to install default parameters for BIOS.
A set of producers have equipped their motherboards with a switch that can be called, for example, Configure. This switch gives an opportunity to control changes of bus frequency, multiplying ratio and the voltage supplied to a processor, memory modules and video card from BIOS. For example, a parameter “CPU Freq Select” has got two values: Hardware and Software. The first value indicates the usage of appropriate jumpers on a motherboard, and the second value indicates the possibility to change multiplier via the software using BIOS.
To change the multiplying ratio, open a section “Frequency/Voltage Control” and select a parameter “CPU Ratio” (CPU System Frequency Multiple, CPU Freq Ratio, Multiplier Factor). Select the required multiplier which may have the following values: 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5 and other; or 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 2:5, 2:7, 2:9, 2:11, 2:13, 2:15 and other.
Some parameters, for example Processor Speed, have got a set of values that directly indicate the processor frequency: 233, 266, 300 and other. But, in fact, this parameter changes the multiplying ratio at a constant bus frequency that is equal, for example, to 66 MHz.