HP Vectra XA 5/xxx HP Vectra xA 5/XXX Series 5 /vl 5/xxx series 5 pc Technical - Page 31

2 System Board Devices on the Processor-Local Bus Bus Frequencies The location of the system board switches is shown in the diagram on page 20. Five of these switches (SW-1,2,3,4 and 7) determine the working frequencies of the PC, and the three frequency multipliers (M1, M2 and M3), as summarized in the table below. The uses of the other switches are summarized on page 39. There is a 14.318 MHz crystal oscillator on the system board whose frequency is multiplied, by a phase locked loop, to 50, 60 or 66 MHz for the Processor Local (PL) bus, according to the settings of SW-1 and SW-2. This is further multiplied, to the processor core frequency, by a factor of 1.5, 2, 2.5 or 3, according to the settings of SW-3 and SW-4. The PCI bus works at half the frequency of the PL bus. The ISA bus works at a third or a quarter of the frequency of the PCI bus, according to the setting of SW-7. You will need to change these switches when you replace the original system board, for a repair, so as to match the processor. You will not need to change the switches if you upgrade the original processor using the correct Intel Overdrive. It is not recommended to upgrade to another processor that may have different voltage requirements. Processor Frequency M1 PL Bus Frequency M2 PCI Bus Frequency M3 ISA Bus Frequency PL Frequency SW-1 SW-2 SW-8 Multiplier M1 SW-3 SW-4 M3 SW-7 VRM1 75 MHz2 1.5 50 MHz 2 25 MHz 3 8.33 MHz Closed Closed Closed Open Open Open Vcc 90 MHz2 1.5 60 MHz 2 30 MHz 4 7.5 MHz Closed Open Closed Open Open Closed Vcc 100 MHz2 1.5 66 MHz 2 33 MHz 4 8.25 MHz Open Closed Closed Open Open Closed Vcc 120 MHz2 2 60 MHz 2 30 MHz 4 7.5 MHz Closed Open Closed Closed Open Closed Vcc,Vre 133 MHz 2 66 MHz 2 33 MHz 4 8.25 MHz Open Closed Closed Closed Open Closed Vcc 150 MHz 2.5 60 MHz 2 30 MHz 4 7.5 MHz Closed Open Closed Closed Closed Closed Vcc,Vmmx 166 MHz 2.5 66 MHz 2 33 MHz 4 8.25 MHz Open Closed Closed Closed Closed Closed Vre,Vmmx 200 MHz 3 66 MHz 2 33 MHz 4 8.25 MHz Open Closed Closed Open Closed Closed Vre,Vmmx 233 MHz2 3.5 66 MHz 2 33 MHz 4 8.25 MHz Open Closed Open Open Open Closed Vmmx 1.Where there is a choice indicated, install the one that is appropriate for the given processor. 2.These processors are not available for these models of HP Vectra PC at the time of printing. This information is provided for completeness only. 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. 31