Friday, 20 September 2013

Pentium Pro

Pentium Pro
Pentium Pro is a pure RISC processor. It is optimized for 32 bit processing in Windows NT or
OS/2. It is unique in that the L2 cache is built-in. This is like two chips in one.
Pentium Pro development started in 1991, in Oregon. It was introduced in late 1995. The new
features were:
Built in optimized L2 cache with 256 KB or 512 KB. This is connected to the CPU itself
with a 64 bit back side bus. Thus, the L2 cache runs synchronous with the CPU speed.
l   
Multiple branch prediction, where the CPU anticipates the next instruction. Data Flow
Analysis, which should reduce data dependence. Speculative Execution, where the CPU
attempts to anticipate instruction results.
l   
5.5 million transistors in the CPU, 15 million for the 256 KB SRAM L2 cache. (6
transistors per bit).
l   
l   4 pipelines for simultaneous instruction execution.
RISC instructions with concurrent x86 CISC code to MicroOps RISC instructions
decoding.
l   
l   2.9 Volt 4 layer BiCMOS processor technology.
Patented protocol. Thus, other CPU manufacturers cannot use the Pentium Pro socket
and chip set. This is not to the users advantage.
l   
Here you see a rectangular chip. The CPU and L2 cache are separate units inside this chip



Pentium Pro is primarily optimized to 32 bit program execution. Since I use a PPro 200 MHZ
(which runs at 233 MHZ) and experience tremendous power in my Windows 95 environment, I

can recommend it for ordinary use.Pentium Pro is especially designed for Windows NT and other genuine 32 bit environments.
Since the introduction of Pentium II, the price on PPro has dropped and soon it will be out of
production.

Pentium II
Pentium Pro "Klamath" was the code name for Intel's new top processor. It is a partially
reduced and partially improved Pentium Pro model. The construction of Pentium II is interesting
but also controversial.
l   With MMX instructions
l   Improved 16 bit program execution (joy for Windows 3.11 users)
l   Doubled and improved L1 cache (16 KB + 16 KB)
CPU is mounted together with 512 KB L2 on a cartridge connected to the main
board using the slot one connector.
l   
l   New increased internal speed: from 233 MHZ to 333 MHZ
The most interesting change is the separation of CPU and L2 cache. Intel found it too costly to
combine them in one chip as in Pentium Pro. To facilitate mass production, cache RAM of a
different brand (Toshiba) was used. The cache RAM is marked 7 ns allowing a clockfrequency
of maximum 150 MHZ.
Pentium II is a large rectangular plastic box, which contains the CPU and cache. There is also
a small controller (S82459AB) and a well dimensioned cooling fan. All are mounted on a card.
This card with chips weighs about 380 g (13 ounces). It fits in a new 242 pin Single Edge
Connector on the system board.
Here you see the SEC-module:


With the new design, the L2 cache has its own bus. It runs at half the CPU speed, like 133
MHZ. This is clearly a retrogression from the Pentium Pro, which can run at 200 MHZ between
the CPU and L2 cache. It is countered by the improved L1 cache, which really zips along! Here
you see a comparison:

Pentium II is Intel's top model. It is currently available in 233, 266, 300, 333, 350 and 400 MHZ

editions. With the new 82440LX and 82440BX chip sets Pentium II is an excellent performer.

No comments:

Post a Comment