Cache Memory - HP 525 5/XX Technical Reference Manual

Switch
Processor-
Local Bus
1 2
Frequency
Open Closed 66 MHz
Closed Open 60 MHz
Open Closed 66 MHz
The computer will execute erratically, if at all, if the configuration switches
are set to operate at a higher processor speed than the processor is capable
of supporting. This may cause damage to the PC.
Setting the switches to operate at a slower speed than the processor is
capable of supporting would not cause any failure of operation but would
cause instructions to be executed more slowly than they should be.

Cache Memory

The PC allows for the provision of two levels of cache memory:
• Level-one cache memory which is fabricated by Intel in the Pentium
processor chip
• Level-two cache memory is optionally installed as a memory module on
the system board
Each acts as temporary storage for data and instructions from the main
memory. Since the system is likely to use the same data several times, it is
faster to get it from the on-chip level-one cache than from the main memory.
The level-two cache memory, when fitted, has a 32-byte line size (a line is an
area of memory of a fixed size). It is controlled by the PL/PCI bridge chip
(SB82437FX). A single HP cache memory module consists of 256 KB of
direct mapped, synchronous or asynchronous, static random access memory
(SRAM). The synchronous cache memory module achieves 10% better
performance than the asynchronous module.
3 System Board (P/Ns D3657-63001 and D3661-63001)
Switch
3 4 7
Closed Closed Closed
Open Closed Closed
Open Closed Closed
Devices on the Processor Local Bus
Frequency
Ratio Processor
(Processor: Frequency
Local Bus)
2.5 166 MHz
3.0 180 MHz
3.0 200 MHz
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