Klamath The original
Klamath Pentium II microprocessor (Intel product code 80522) ran at 233, 266, and 300
MHz and was produced in a 0.35
μm process. The 300 MHz version, however, only became available in large quantities later in 1997. Pentium II-based systems using the
Intel 440LX Balboa chipset widely popularized
SDRAM (which was to replace
EDO RAM and was already introduced with 430VX), and the
AGP graphics bus. On July 14, 1997, Intel announced a version of the Pentium II
Klamath with 2× 72-bit ECC L2 cache for entry-level servers, as opposed to the 2× 64-bit non-ECC L2 cache on regular models. The extra bits give it error-correction capability built into hardware, without impacting performance. The variant can be determined through the CPU part number. In Intel's "Family/Model/Stepping" scheme, Klamath CPUs are family 6, model 3.
Deschutes The
Deschutes core Pentium II (80523), which debuted at 333 MHz in January 1998, was produced with a 0.25
μm process and has a significantly lower power draw. Towards the end of its design life, Deschutes chips capable of 500 MHz within Intel cooling and design specifications were produced. However, these were not marketed. Rather than destroy already multiplier-locked units, those Deschutes units that had been tested and locked with a multiplier of 5 were sold as being 333 MHz. This was accomplished by disabling the 100 MHz bus option.
Overclockers, upon learning of this, purchased the units in question and ran them well over 500 MHz; most notably, when overclocking, the final batch of "333 MHz" CPUs were capable of speeds much higher than CPUs sold at 350, 400, or 450 MHz. Concurrent with the release of Deschutes cores supporting a 100 MT/s front-side bus was Intel's release of the
440BX Seattle chipset and its derivatives, the 440MX, 450NX, and 440ZX chipsets. Replacing the aged 66 MHz FSB, which had been on the market since 1993, the 100 MHz FSB resulted in solid performance improvements for the Pentium II lineup. Pentium II chips starting with 350 MHz were released in both SECC and SECC2 form factors. Late Pentium IIs also marked the switch to
flip-chip based packaging with direct heatsink contact to the die, as opposed to traditional bonding. While
Klamath features 4 cache chips and simulates dual-porting through interleaving (2x 64-bit) for a slight performance improvement on concurrent accesses,
Deschutes only sports 2 cache chips and offers slightly lower L2 cache performance at the same clockspeed. Furthermore,
Deschutes always features ECC-enabled L2 cache. The
Pentium II Xeon was a high-end version of Deschutes core intended for use on
workstations and
servers. Principally, it used a different type of slot (
Slot 2), case, board design, and more expensive full-speed custom L2 cache, which was off-die. Versions were produced with 512 KB, 1 MB or 2 MB L2 caches by varying the number of 512 KB chips incorporated on the board. In Intel's "Family/Model/Stepping" scheme, Deschutes CPUs are family 6, model 5 and have the part number 80523.
Pentium II OverDrive In 1998, the 0.25 μm Deschutes core was utilized in the creation of the
Pentium II Overdrive processor, which was aimed at allowing corporate
Pentium Pro users to upgrade their aging servers. Combining the Deschutes core in a
flip-chip package with a 512 KB full-speed L2 cache chip from the Pentium II Xeon into a
Socket 8-compatible module resulted in a processor that could run at 300 or 333 MHz on a 60 or 66 MHz front-side bus. This combination brought together some of the more attractive aspects of the Pentium II and the Pentium II Xeon:
MMX support/improved 16-bit performance and full-speed L2 cache, respectively. The later "Dixon" mobile Pentium II would emulate this combination with 256 KB of full-speed cache. In Intel's "Family/Model/Stepping" scheme, the Pentium II OverDrive CPU identifies itself as family 6, model 3, though this is misleading, as it is not based on the family 6/model 3 Klamath core. As mentioned in the Pentium II Processor update documentation from Intel, "although this processor has a CPUID of 163xh, it uses a Pentium II processor CPUID 065xh processor core."
Tonga The 0.25 μm
Tonga core was the first mobile Pentium II and had all of the features of the desktop models. In Intel's "Family/Model/Stepping" scheme, Tonga CPUs are family 6, model 5.
Dixon Later, in 1999, the 0.25; 0.18 (400
MHz) μm
Dixon core with 256 KB of on-die full speed cache was produced for the mobile market. Reviews showed that the Dixon core was the fastest type of Pentium II produced. In Intel's "Family/Model/Stepping" scheme, Dixon CPUs are family 6, model 6 and their Intel product code is 80524. These identifiers are shared with the
Mendocino Celeron processors. ==Core specifications==