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Devices on the processor-local bus – HP Vectra VL 5/xxx Series 5 User Manual

Page 30

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2 System Board

Devices on the Processor-Local Bus

Devices on the Processor-Local Bus

The Intel Pentium Microprocessor

The Pentium processor is packaged in a pin-grid-array (PGA), and is
seated on the system board in a zero-insertion-force (ZIF) socket 7. Only
upgrades that are pin compatible with the original processor, manufactured
by Intel, are supported.

P54CS chips working at 133 and 150 MHz (along with P54C chips working at
75, 90, 100 MHz and new versions of the 120 MHz chip) require a 3.3 V
supply. A passive shorting block is sufficient to connect the regulated 3.3 V
output of the power supply directly to the Pentium processor.

P54CS chips working at 166 and 200 MHz require between 3.45 and 3.60 V.
They need an VRE voltage regulator module (VRM), in which the voltage
is actively derived from the 3.3 V, 5 V and 0 V outlets of the power supply.

P55C chips, with MMX technology, require two voltage supplies: 3.3 V for
the input and output buffers, and 2.8 V for the core logic. It requires an
active VRM that is specifically designed for use with the MMX processor.
This VRM can be identified by the inscription “2.8 V” marked on the board.

Any thermal contact material between the processor and the heat-sink must
not be removed or disturbed. The cooling needs of the processor are critical.

MMX Technology

The instruction set of the MMX processor includes 57 new instructions, four
new 64-bit data formats (depicted below) and eight new 64-bit MMX
registers. As well as the pipelined parallelism of the traditional Pentium
architecture, MMX is capable of SIMD parallelism (single-instruction/
multiple-data). Instead of combining a pair of operands to produce a single
result, each instruction is able to gang each operation over a large number of
pairs of operands, so producing a large number of results concurrently. This
type of parallelism is particularly useful when processing large vectors and
arrays of data (in graphics and audio processing, for example).

Quadword

64 bit

Packed double word

32 bit

32 bit

Packed word

16 bit

16 bit

16 bit

16 bit

Packed byte

8 bit

8 bit

8 bit

8 bit

8 bit

8 bit

8 bit

8 bit