HP Vectra VA 6/xxx HP Vectra VA 6/xxx and XA 6/xxx pc - technical reference ma - Page 24

2 System Board Devices on the Processor-Local Bus Bus Frequencies 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 Frequency 150 MHz 166 MHz 180 MHz 200 MHz 233 MHz 266 MHz Switch Switch 1 2 Closed Open Open Open Closed Open Open Open Open Open Open Open Processor Local Bus Frequency 60 MHz 66 MHz 60 MHz 66 MHz 66 MHz 66 MHz Switch Switch Switch 3 4 5 Open Open Open Open Open Closed Open Open Closed Closed Closed Open Closed Closed Open Open Closed Open Frequency Ratio Processor : Local Bus 2.5 : 1 2.5 : 1 3 : 1 3 : 1 3.5 : 1 4 : 1 16