Hardware Reference
In-Depth Information
Photo 1.7
A modern Slot 1 Pentium processor
increased data throughput. The architecture of the Pentium Pro was optimized
for 32-bit code, but the chip would only run 16-bit code at the same speed as
its predecessor.
Originally released in 1997, the Pentium MMX was intended to improve
multimedia performance although software had to be specially written for it to
have an effect. This software had to make use of the new MMX instruction set
that was an extension off the normal 8086 instruction set. Other improvements
produced a chip that could run faster than previous Pentiums.
Optimized for 32-bit applications, the Pentium 2 had 32 KB of level 1 cache
(16 KB each for data and instructions) and had a 512 KB of level 2 cache on
package. To discourage competitors from making direct replacement chips, this
was the first Intel chip to make use of its patented 'Slot 1'. The Intel Celeron
was a cut down version of Pentium II aimed primarily at the laptop market.
The chip was slower as the level 2 cache had been removed. Later versions
were supplied with 128 KB of level 2 cache.
The Pentium III was released in February 1999 and first made available in a
450 MHz version supporting 100 MHz bus. As a means of further improving
the multimedia performance of the processor (particularly for 3D graphics), the
Pentium III supports extensions to the MMX instruction set.
The latest Pentium 4 architecture is based on new 'NetBurst' architecture
that combines four technologies: Hyper Pipelined Technology, Rapid Execution
Engine, Execution Trace Cache, and a 400 MHz system bus. The Pentium 4
processor (see Photo 1.7) is available at speeds ranging from 1.70 to 2.80 GHz
with system bus speeds of 400 and 533 MHz (the latter delivering a staggering
4.2 GB of data-per-second into and out of the processor). This performance is
accomplished through a physical signalling scheme of quad pumping the data
transfers over a 133-MHz clocked system bus and a buffering scheme allowing
for sustained 533 MHz data transfers.
