Hardware Reference
In-Depth Information
OnOctober19,1992,Intelannouncedthatthefifthgenerationofitscompatiblemicropro-
cessor line (code-named P5) would be named the Pentium processor. The actual Pentium
chip shipped on March 22, 1993. Systems that used these chips were only a few months
behind.
Note
Pentium, like Celeron and Athlon, has become a brand name in recent years rather than
identifyingaparticularprocessortype.ThissectiondiscussestheoriginalPentiumprocessors
for Socket 5 and Socket 7.
ThePentiumisfullycompatiblewithpreviousIntelprocessors,butitdiffersfromthemin
many ways. At least one of these differences is revolutionary: The Pentium features twin
data pipelines, which enable it to execute two instructions at the same time. The 486 and
all preceding chips can perform only a single instruction at a time. Intel calls the capabil-
ity to execute two instructions at the same time
superscalar technology
. This technology
provides additional performance compared to the 486.
With superscalar technology, the Pentium can execute many instructions at a rate of
two instructions per cycle. Superscalar architecture usually is associated with high-output
RISC chips. The Pentium is one of the first CISC chips to be considered superscalar. The
Pentium is almost like having two 486 chips under the hood.
Table 3.12
shows the Penti-
um processor specifications.
Table 3.12 Pentium Processor Specifications
