User Guide

Hardware Installation
2-7
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
Intel Pentium, Cyrix 6x86 and AMD
K5/K6 CPU are designed to have
different Internal (Core) and
External (Bus) frequency. The ratio
of Core/Bus frequency is selected
by JP1 and JP2, which CPU is
using to multiply external clock and
produce internal frequency.
Core frequency = Ratio * External bus clock
JP1 & JP2
3 2 1
3 2 1
1.5x (3.5x)
JP1 & JP2
3 2 1
3 2 1
2.5x (1.75x)
JP1 & JP2
3 2 1
3 2 1
2x
JP1 & JP2
3 2 1
3 2 1
3x
Note: The feature CPU Intel PP/MT 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.
Note: The future CPUs have not been tested by AOpen
Quality Test Department. It is possible that this mainboard can
not support these future CPUs.
JP3
2-3
1-2
2-3
JP4
2-3
2-3
1-2
JP13
1-2 5-6
1-2 3-4
3-4
CPU External
Clock
50MHz
60MHz
66MHz
JP3, JP4 and JP13 are the
selections of CPU external
clock (bus clock), which is
actually the clock from clock
generator.