HP Kayak XA Technical Reference Manual page 37

Bus Frequencies
Processor
Frequency
233 MHz
266 MHz
300 MHz
333 MHz
1.
Processor bus frequency is always set at 66MHz for all XA PC Workstations models.
2.
Switches are provided to match the system board to processor frequency when a
system board repair is performed.
There is a 14.318 MHz crystal oscillator on the system board. This frequency
is multiplied to 66 MHz by a phase locked loop. This is further scaled by an
internal clock multiplier within the processor.
For example, the Pentium II 300 MHz processor multiplies the 66 MHz
system clock by 4.5. Switches 1 and 2, on the system board switches, set the
frequency of the Processor-Local bus, which for all HP Kayak XA PC
Workstation models, is 66 MHz. Switches 3, 4 and 5 set the clock multiplier
ratio.
Switch
Processor
Local Bus
1 2 Frequency
Open Open 66 MHz
Open Open 66 MHz
Open Open 66 MHz
Open Open 66 MHz
The computer may execute erratically, if at all, or may overheat, if it is
configured to operate at a higher processor speed than the processor is
capable of supporting. This can cause damage to the computer.
Setting the switches to operate at a slower speed, than the processor is
capable of supporting, can still cause erratic behavior in some cases, and
would reduce the instruction throughput in others.
PCI Bus ISA Bus
Frequency Frequency
1
33 MHz 8.25 MHz
33 MHz 8.25 MHz
33 MHz 8.25 MHz
33 MHz 8.25 MHz
2 System Board
Devices on the Processor-Local Bus
2
Switch
3 4 5
Open Closed Closed
Closed Open Open
Closed Open Closed
Closed Closed Open
Frequency
Ratio
Processor:
Local Bus
3.5 : 1
4 : 1
4.5 : 1
5 : 1
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