CPU Clock

The very first setting that needs to be made in the BIOS is to adjust the motherboard to utilizing the proper clock settings for the CPU installed in the computer. Most modern BIOS vendors can detect the type of CPU and automatically set the proper timings. Refer to the documentation from the CPU and motherboard vendor for the proper settings.

The CPU speed is comprised of two numbers, a bus speed and a multiplier. The bus speed is the tricky part because vendors may have this setting done either at the natural clock rate or at the enhanced clock rate. The natural front side bus is the more common of the two. The multiplier is then used to determine the final clock speed based on the bus speed of the processor. Set this to the appropriate multiple for the final clock speed of the processor.

For an example, if you have an AMD Athlon XP 2500+ processor that has a CPU speed of 1.82GHz clock, the proper settings for the BIOS would be a bus speed of 166MHz and a multiplier of 11. (166MHz x 11 = 1.826 GHz)