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Hyper Pipelined Technology:
The hyper-pipelined technology of the NetBurst micro-architecture doubles the pipeline depth compared to
the P6 micro-architecture used on today’s Pentium III processors. One of the key pipelines, the branch
prediction/ recovery pipeline, is implemented in 20 stages in the NetBurst micro-architecture, compared to
10 stages in the P6 micro-architecture. This technology significantly increases the performance, frequency,
and scalability of the processor.
400 MHZ System Bus:
The Pentium4 processor supports Intel’s highest performance desktop system bus by delivering 3.2 GB
of data per second into and out of the processor. This is accomplished through a physical signaling scheme
of quad pumping the data transfers over a 100-MHz clocked system bus and a buffering scheme allowing
for sustained 400-MHz data transfers. This compares to 1.06 GB/s delivered on the Pentium III processor’s
133-MHz system bus.
Level 1 Execution Trace Cache:
In addition to the 8KB data cache, the Pentium 4 processor includes an Execution Trace Cache that stores
up to 12K decoded micro-ops in the order of program execution. This increases performance by removing
the decoder from the main execution loop and makes more efficient usage of the cache storage space since
instructions that are branched around are not stored. The result is a means to deliver a high volume of
instructions to the processor’s execution units and a reduction in the overall time required to recover from
branches that have been mis-predicted.
