SOYO SY-6VBA 133 User Manual page 45

Hardware Installation SY-6VBA 133
As example, if JP7 is set to open and JP2 to (1-2), the boot-up FSB
frequency will be 100MHz. When the BIOS takes control, it will write the
BIOS FSB setting to the clock generator. This happens shortly after
power-up, and the FSB frequency will then be in accordance to the BIOS
setting. The group from which the FSB Frequency can be selected in the
BIOS is 90~122MHz and AGP Clock will be 60~81MHz. Note that all
FSB Frequencies are available in the BIOS, but that only those in the
group as determined by JP2 and JP7 will have effect when selected.
Step 4. CPU B21 and A14 Settings: JP8 and JP9
For certain Intel CPUs, the multiplier is not locked such that setting a multiplier
higher than specified on the CPU is possible. For technical details read the
following:
Your PII /III 100/66 MHz FSB CPU has an input pin B21 (100/66# signal) to tell
it what FSB frequency it is running at; The PIII 133 MHz FSB CPU has two pins
B21and A14 (133/100# signal). JP8 and JP9 are connected to the B21 and A14
input respectively and are used to tell CPU its FSB speed.
The actual FSB Frequency is however set through the BIOS and it may
therefore differ from the Frequency specified to the CPU through JP8 & JP9.
Because some INTEL CPUs have their multipliers limited at a FSB Frequency
of 100MHz and higher, telling the CPU that it is running at 66MHz through JP8
& JP9 while setting a different (higher) FSB Frequency in the BIOS may allow
the user to set a higher multiplier value. Doing so will however force your CPU
to operate out of its specifications, and therefore SOYO can not guarantee the
proper functioning of your system.
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