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An
eternity has passed it seems, since Intel has
released a processor based on an entirely new
architecture. In actuality, it's been 5 years
to be exact, since the P6 Micro-Architecture was
introduced in 1995. Against the backdrop of
the perpetual design cycles of the Semiconductor
Industry, in 5 years a lot can change.
However,
mainstream processor base cores are not trivial to
design. Also, Intel has a pretty good knack of
leaving themselves the hooks in the technology that
will allow roadmap products at higher frequencies
with more features, to carry them forward with
relatively minor iterations of the base
product. It seems as though Intel has milked
the P6 core for all it is worth now and has finally
hit the wall with respect to clock frequency.
The Pentium III will top out at roughly 1GHz. and
faced with a growing competitive environment as well
as the end user's insatiable need for speed, Intel
needed to "reinvent the wheel".
Perhaps not totally reinventing it but a major
overhaul was in order.
In the
following pages we'll show you the inner workings of
the all new Pentium 4 Processor, the Motherboard and
Chipset that supports it and the performance levels
that are to be expected across various software
applications and operating systems.
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| Specifications
Of The Pentium 4 NetBurst Micro-Architecure |
| .18
Micron, 42 Million Transistors and a
little attitude adjustment |
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Introductory
1.4GHz. and 1.5GHz. Clock Speed with roadmap
to 2GHz. and beyond
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400MHz.
"Quad Pumped" System Bus
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"Hyper
Pipelined" Technology - 20 stage
pipeline depth for greater frequency capability
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"Rapid
Execution Engine" - ALUs run at
twice the speed of the core frequency
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256K
L2 Advanced Transfer Cache running at core
processor speed
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8K
L1 Data Cache
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Execution
Trace Cache - Caches decoded Micro-Ops
readying them for execution
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Advanced
Dynamic Execution - More efficient
speculative out of order execution unit feeding
execution engines
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Enhanced
Branch Prediction Capability - Compensates
for the deeper pipeline's higher likelihood of
mis-predicted branches
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Streaming
SIMD Extension 2 (SSE2) - 144 New
instructions including 128bit SIMD Integer
Arithmetic and 128bit double precision floating
point instructions in addition to SSE and MMX
instructions.
Click
images for full view
Things certainly have changed for the Pentium 4 and
clock speed is only one of many aspects that are
completely upscale versus its predecessor. The
way Intel was able to get the core speed up was by
deepening the CPU's pipeline. This allows for
higher core frequencies but also increases the
chance for missed directed branch predictions.
Branch predictions are the way most x86 processors
today anticipate what instruction they will execute
next. In a addition, because the pipeline is
twice as deep as say the Pentium 3, the Pentium 4
pays a higher performance penalty for those missed
branch predictions.
In
addition, a deeper pipeline also means fewer
instructions per clock cycle can be executed.
This situation is more than compensated for as long
as you can achieve the substantially higher clock
frequency that the P4 has at 1.5GHz. versus a 1GHz.
Pentium 3. In order to offset some of these
concessions Intel had to make with the deeper
pipeline, they have also incorporated many new
enhancements to their design including adding
Execution Trace Cache for decoded Mico-Ops, better
speculative out of order execution, an enhanced
Floating Point Unit, Arithmetic Logic Units running
at twice the speed of the core, SSE2 Instructions
and a 400MHz. System Bus.
So,
the Pentium 4's architecture sounds pretty beefy but
what about the Motherboard, Chipset and other
hardware that support it? Enter our Pentium 4
"White Box" Test System. Let's have
a look...
The
Pentium 4 White Box and D850GB Motherboard
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