User Guide

Hardware Installation
2-9
2.2.2 Selecting the CPU Frequency
JP1
1-2
2-3
2-3
1-2
JP2
1-2
1-2
2-3
2-3
CPU Frequency
Ratio
1.5x (3.5x)
2x
2.5x (1.75x)
3x
The Intel Pentium, Cyrix 6x86 and
AMD K5/K6 CPUs have different
internal (Core) and external (Bus)
frequency. The ratio of Core/Bus
frequency that the CPU uses to
multiply the external clock and
produce internal frequency is selected
by setting JP1 and JP2.
Core frequency = Ratio x External
bus clock
JP1 & JP2
1 2 3
1.5x (3.5x)
JP1 & JP2
1 2 3
2.5x (1.75x)
JP1 & JP2
1 2 3
2x
JP1 & JP2
1 2 3
3x
Note: Intel PP/MT MMX 233MHz is using 1.5x
jumper setting for 3.5x frequency ratio, and AMD
PR166 is using 2.5x setting for 1.75x frequency
ratio.
JP3
2-3
1-2
2-3
JP4
2-3
2-3
1-2
CPU External Clock
50MHz
60MHz
66MHz
JP3 and JP4 let you set the CPU
external clock (bus clock), i.e., the
clock generator frequency.