Intel Pentium II

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Intel Pentium II Processor Logo.svg
Logo of the Intel Pentium II
Production: 1997 to 2001
Producer: Intel
Processor clock: 233 MHz to 450 MHz
FSB cycle: 66 MHz to 100 MHz
L2 cache size: 256 KiB to 512 KiB
Manufacturing : 0.35 µm to 0.25 µm
Instruction set : x86 (16 bit) and x86-32
Microarchitecture : P6
  • Slot 1
  • MMC-1 / MMC-2
  • Mini cartridge
  • BGA
  • μPGA
Names of the processor cores:
  • Klamath, Deschutes
  • Tonga, Dixon
Pentium II processor
Back of an opened Klamath processor module. In the middle the cache controller, left and right cache modules

The Pentium II is an x86 -compatible main processor (CPU) from the manufacturer Intel from the P6 processor family.


The Pentium II core was based on the Pentium Pro , but could execute 16-bit code much faster than the latter. He also mastered the MMX instruction set introduced in the Pentium MMX . Unlike its predecessor, the Pentium Pro are the Pentium II, the cache is not on the processor , the integrated, but as external cache modules together soldered to the processor core on a board, the voluminous in a pretty, black plastic housing ( SECC ) with a large Hologram sticker and a printed white "Pentium II" lettering was housed, which set the Pentium II apart from all previous processor generations in terms of appearance. In a slightly different form ( SECC2 ) it was used both in the first ( Katmai ) and partly in the second ( Coppermine ) Pentium III generation. To manage the L2 cache, an additional chip, the cache controller, is required, which was also located on the board together with the processor and the cache modules. Instead of a socket for the processor, there was a slot on the motherboard due to the design . This was designated by Intel as slot 1 . The processor was inserted upright into it and locked with latches on the side. Compared to the Pentium Pro, external cache modules were a step backwards, but they solved the problem of the low chip yield with the Pentium Pro. In this way, Intel was able to manufacture the Pentium II at prices that were acceptable to the mass market, despite the costs associated with the case. However, advances in semiconductor production soon made this solution, which was chosen for cost reasons, superfluous, so that from the second revision of the Pentium III ( Coppermine ) the L2 cache was back on the processor die and instead of a slot with a plug-in card again on a conventional FC- PGA construction with base was converted.

The first Pentium II " Klamath " presented in May 1997 ran at clock rates of 233, 266 and 300 MHz and generated (for the time) a large amount of waste heat. The cause was the 0.35 µm manufacturing process, which required a core voltage of 2.8 volts. With their FSB of 66 MHz, they lagged behind the actual potential of CPU design. Compared to the successor, the multipliers in the Klamath were not hard-wired (locked): With most processors, smaller multipliers could be used, so that a Pentium II 300 could run at 3 × 100 MHz (instead of 4.5 × 66 MHz) without it in result to overclock. In some models, the multiplier could also be successfully increased upwards.

In January 1998 the Pentium II " Deschutes " had its premiere with 333 MHz. It was manufactured in a 0.25 µm process and only needed 2.0 volts of core voltage, which resulted in significantly less heat dissipation. Support for an FSB of 100 MHz from the 350 MHz model onwards brought considerable performance gains. For the first time it was possible to control more than 512 MiB RAM with the L2 cache (up to 4 GiB). During the year Pentium II processors with 350, 400 and 450 MHz were released. To make overclocking more difficult, almost all of these processors had the multiplier hardwired internally.

A special feature was the Deschutes processor of the SL2W8 series (see picture above), which ran with only 66 MHz FSB and 300 MHz core clock. These processors quickly became an insider tip in the overclocking scene, as many of them were equipped with the same cache components that were also used in the 450 MHz Deschutes. Since every Deschutes core could be operated with 100 MHz FSB, it was in many cases possible to overclock the SL2W8 to over 450 MHz.

In addition to the Pentium II, a reduced-performance version of the processor for the low-price segment was offered for the first time, the Intel Celeron . The main difference to a full-fledged Pentium II were changes to the L2 cache (at first none and then 128 KiB) and the generally limited FSB clock rate of 66 MHz. The associated performance losses were sometimes considerable, which initially gave the name a bad reputation.

Together with the Pentium II, Intel introduced suitable chipsets such as 440LX or 440BX, which support the AGP bus as a fast, dedicated connection to the graphics card.

Desktop models

Klamath (A80522)

Pentium II with 266 MHz (Klamath)
Pentium II (Klamath) without case
  • L1 cache : 16 + 16 KiB (data + instructions)
  • L2 cache: 512 KiB, four external cache components on CPU module with half the processor clock
  • Slot 1 , GTL + with 66 MHz front side bus
  • Operating voltage ( VCore ): 2.8 V.
  • Release DATE: May 7, 1997
  • Manufacturing technology: 0.35 µm
  • The size: 203 mm² with 7.5 million transistors
  • Clock frequencies: 233, 266 and 300 MHz
  • TDP (max. W):
    • 233 MHz: 34.8
    • 266 MHz: 38.2
    • 300 MHz: 43

Deschutes (A80523)

Pentium II with 350 MHz (Deschutes)
  • L1 cache : 16 + 16 KiB (data + instructions)
  • L2 cache: 512 KiB, two external cache components on CPU module with half the processor clock
  • Slot 1 , GTL + with 66 and 100 MHz front side bus
  • Operating voltage ( VCore ): 2.0V
  • Release DATE: January 26, 1998
  • Manufacturing technology: 0.25 µm
  • The size: 131 mm² (later 118 mm²) with 7.5 million transistors
  • Clock frequencies: 266 to 450 MHz
    • 66 MHz FSB: 266, 300, 333 MHz
      • TDP (max. W):
        • 266 MHz: 16.8
        • 300 MHz: 18.6
        • 333 MHz: 20.6
    • 100 MHz FSB: 350, 400, 450 MHz
      • TDP (max. W):
        • 350 MHz: 21.5
        • 400 MHz: 24.3
        • 450 MHz: 27.1

Mobile models

Tonga (80523)

Mobile Pentium II (Tonga)
  • L1 cache: 16 + 16 KiB (data + instructions)
  • L2 cache: 512 KiB, external L2 chips run at half the clock frequency
  • Housing: MMC-1, MMC-2, mini-cartridge
  • Front Side Bus : 66 MHz, GTL +
  • Operating voltage (Vcore): 1.6V
  • Manufacturing technology: 0.25 µm CMOS
  • Release DATE: June 7, 1997
  • Clock frequencies: 233, 266 and 300 MHz
  • TDP (max. W):
    • 300 MHz: 11.6
    • 266 MHz: 10.3
    • 233 MHz: 9.0

Dixon (80524)

Intel Mobile Pentium II (Dixon) with 400 MHz
  • L1 cache: 16 + 16 KiB (data + instructions)
  • L2 cache: 256 KiB, on-die, full speed.
  • Package: BGA , MMC-1, MMC-2, μPGA
  • Front Side Bus : 66 MHz, GTL +
  • Operating voltage (Vcore): 1.5V, 1.55V, 1.6V, 2.0V
  • Manufacturing technology: 0.25 µm CMOS
  • Release DATE: January 25, 1999
  • Clock frequencies: 266, 300, 333, 366 and 400 MHz

See also


Datasheets from Intel:

Web links

Commons : Pentium II  - collection of pictures, videos and audio files