Devices On The Processor-Local Bus; Intel Pentium Pro Microprocessor - HP Vectra VA6 Technical Reference Manual

Bus Frequencies
2 System Board

Devices on the Processor-Local Bus

Devices on the Processor-Local Bus

Intel Pentium Pro Microprocessor

The processor that is supplied can be P6 or P6S. The processor is packaged
in a 387-way pin-grid-array (PGA), which is seated on the system board in
a P6T overdrive zero-insertion-force (ZIF) socket 8. Only upgrades using
OverDrive processors, pin compatible with the original processor,
manufactured by Intel, are supported.
The voltage regulator module (VRM) is implemented directly on the
system board. The voltage is selected automatically by the processor (four
logic signals specify a voltage between 2.0 V to 3.5 V in steps of 0.1 V).
The cooling needs of the processor require there to be a good thermal
contact between it and the heat-sink. A thermal contact material made of
silicone-based grease, or of aluminium foil, must be placed on the top of the
processor before installing the heat-sink.
Although it is not pin compatible with the Pentium, the Pentium Pro is
backward code-compatible. Software written for previous HP Vectra PCs
will run on the Pentium Pro-based HP Vectra PCs.
Like the Pentium and 80486 DX2 processors, the Pentium Pro uses internal
clock multiplication. For example, the Pentium Pro 200 MHz processor
multiplies the 66 MHz system clock by three. Switches 1 and 2 on the system
board switches set the frequency of the Processor-Local bus. Switches 3, 4
and 5 set the clock multiplier ratio.
Processor Switch
Frequency 1
150 MHz Closed
166 MHz Open
180 MHz Closed
200 MHz Open
233 MHz Open
266 MHz Open
16
Processor
Switch Switch
Local Bus
2
Frequency
Open 60 MHz
Open 66 MHz
Open 60 MHz
Open 66 MHz
Open 66 MHz
Open 66 MHz
Switch Switch
3 4 5
Open Open Closed
Open Open Closed
Open Closed Open
Open Closed Open
Open Closed Closed
Closed Open Open
Frequency
Ratio
Processor :
Local Bus
2.5 : 1
2.5 : 1
3 : 1
3 : 1
3.5 : 1
4 : 1