Pentium II
From Wikipedia, the free encyclopedia
| Pentium II Central processing unit |
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 A Slot 1 Pentium II – front view |
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| Produced: | From mid 1997 to early 1999 |
| Manufacturer: | Intel |
| CPU Speeds: | 233 MHz to 450 MHz |
| FSB Speeds: | 66 MHz to 100 MHz |
| Process: (MOSFET channel length) |
0.35 µm to 0.25 µm |
| Instruction Set: | x86 |
| Microarchitecture: | P6 |
| Sockets: | |
Cores:
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The Pentium II is an x86 architecture microprocessor by Intel, introduced on May 7, 1997. It was based on a modified version of the P6 core first used for the Pentium Pro, but with improved 16-bit performance and the addition of the MMX SIMD instruction set which had already been introduced on the Pentium MMX.
The original Klamath Pentium II (Intel product code 80522) ran at 233 and 266 MHz, were produced in a 0.35 µm fabrication process and produced (for that time) an incredible amount of heat. A 300 MHz version was released later in 1997. They also worked with a 66 MHz front side bus, which was a speed that was inadequate for the CPU's design to show its full potential.
The Deschutes core Pentium II (80523), which debuted at 333 MHz in January 1998, was produced in a more suitable 0.25 µm fabrication process and ran significantly cooler. The 333MHz was the last of the legacy 66 MHz front side bus. Support for 100 MHz front side bus speeds heralded solid performance improvements. During 1998, Pentium IIs running at 266, 300, 350, 400, and 450 MHz were also released. Pentium II-based systems also saw the introduction of the new generation RAM-standard, SDRAM (which replaced EDO RAM), and the AGP graphics bus.
Unlike previous Intel processors such as the Pentium and Pentium Pro, the Pentium II was packaged in a slot-based form-factor rather than a socket. The chip and associated components were carried on a daughterboard similar to a typical expansion board within a plastic cartridge. A fixed or removable heatsink was carried on one side, sometimes using its own fan. This larger package was a compromise allowing Intel to separate the secondary cache from the processor while still keeping it on a closely coupled bus. This separate cache was slower (running at half the processor speed) than that in the Pentium Pro, but the smallest cache size was increased to 512 KiB from the 256 KiB on the Pentium Pro. Off-package cache solved the Pentium Pro's low yields allowing Intel to introduce the Pentium II at a mainstream price level.
This arrangement also allowed Intel to easily vary the amount of L2 cache, thus making it possible to produce inexpensive but low performance and expensive but high performance versions of the CPU using the same core chip. Intel reverted to the more usual format of placing the processor on the mainboard with the Pentium III but continued the practice of selling essentially similar chips with small and large cache sizes, with the L2 cache moved onto the die itself.
The low-end version of the Pentium II - essentially a Pentium II with less (or no) level 2 cache - was marketed under the name "Celeron". It was not well received by many IT professionals due to substantially lesser performance compared with the more expensive product with L2 cache. However, the lack of the off-die L2 cache allowed for more flexibility with overclocking (the missing L2 cache was more sensitive to overclocking than the main chip). This overclockability led to heat issues, and the Pentium II Celeron was one of the first chips for which aftermarket companies started to produce high performance cooling such as water-based or refrigerant cooling.
The Pentium II Xeon was a high-end version intended for use on servers. Principally, it used a different type of slot (Slot 2), case, board design and used expensive full-speed L2 cache, which was again off-die. Versions were produced with 512 KiB, 1 MiB or 2 MiB L2 caches by varying the number of 512 KiB chips incorporated on the board.
A mobile version with 256 KiB of on-die, full speed cache was produced late in the chip's lifecycle, and was the fastest type of Pentium II. This design was seen in some Celeron based processors such as the 300A which became very popular with enthusiasts due to its low cost, overclocking friendly design and competitive performance. However, the 0.25 µm process did not allow Dixon to be produced in high enough quantities for it to supplant the Deschutes core, thus limiting the chip to the mobile market, which typically commands somewhat higher processor prices than those of desktop processors. It would not be until the advent of the 0.18 µm process and the Pentium III "Coppermine" that a desktop processor with an on-die cache became practical.
By early 1999, the Pentium III superseded the Pentium II.
Contents |
[edit] Models
[edit] Desktop
[edit] Klamath (80522)
- L1 cache: 16 + 16 KiB (Data + Instructions)
- L2 cache: 512 KiB, external chips on CPU module with 50% of CPU-speed
- Slot 1 (GTL+)
- MMX
- Front side bus: 66 MHz
- VCore: 2.8 V
- Fabrication: 0.35 µm
- First release: May 7, 1997
- Clockrate: 233, 266, 300 MHz
[edit] Deschutes (80523)
- L1 cache: 16 + 16 KiB (Data + Instructions)
- L2 cache: 512 KiB, external chips on CPU module with 50% of CPU-speed
- Slot 1 (GTL+)
- MMX
- Front side bus: 66, 100 MHz
- VCore: 2.0 V
- Fabrication: 0.25 µm
- First release: January 26, 1998
- Clockrate: 266 - 450 MHz
- 66 MHz FSB : 266, 300, 333 MHz
- 100 MHz FSB: 350, 400, 450 MHz
[edit] Mobile
[edit] Tonga (80523)
mobile Pentium II
- L1 cache: 16 + 16 KiB (Data + Instructions)
- L2 cache: 512 KiB, external chips on CPU module with 50% of CPU-speed
- MMC-1, MMC-2, Mini-Cartridge (GTL+)
- MMX
- Front side bus: 66 MHz
- VCore: 1.6 V
- Fabrication: 0.25 µm
- First release: June 7, 1997
- Clockrate: 233, 266, 300 MHz
[edit] Dixon (80524)
mobile Pentium II PE ("Performance Enhanced")
- L1 cache: 16 + 16 KiB (Data + Instructions)
- L2 cache: 256 KiB, on-die, full CPU speed
- BGA1, MMC-2, μPGA1 (GTL+)
- MMX
- Front side bus: 66, 100 MHz
- VCore: 1.5, 1.55, 1.6 V, 2.0 V
- Fabrication: 0.25 µm
- First release: January 25, 1999
- Clockrate: 266 - 400 MHz
[edit] External links
- Listing of various PII, PIII, and Celeron alphanumeric model designations
- Intel Pentium II technical specifications
- CPU-INFO: Intel Pentium II, indepth processor history
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