Cyrix III is an x86-compatible Socket 370 CPU. VIA Technologies launched the processor in February 2000. VIA had purchased both Centaur Technology and Cyrix. Cyrix III was to be based upon a core from one of the two companies.
History The Cyrix III was launched in late February 2000. It was initially based on the Joshua core, and was available in two performance ratings of 500 and 533 MHz, with the PR500 being $84 per unit and the PR533 $99. National Semiconductor would be the producer of the chips.
650 and 667 MHz versions of the Cyrix III were available starting January 2001. The 650 MHz version would cost $55 per chip while the 667 would be $60 and both were based on the Samuel core.
The 700 MHz version of the Cyrix III was available on January 19, 2001. The price would be $62 per chip in bulk quantities. This was the last III chip released using the Samuel core, as the Samuel II was expected to be released in March.
Just a month later in February 2001, Cyrix III chips based on the Samuel 2 core were announced. An initial 750 MHz version would be available, with 800 and 850 MHz coming later. The chips would have a 100 and 133 MHz FSB, 128 KB of L1 cache along with MMX and 3DNow instructions. The chips would be produced using a 0.15 micron process and have a die size of 52 square mm. VIA planned to release a later version of the chip, code-named Ezra/C5C with a 0.13 micron process and speeds of 750 MHz up to possibly 1 GHz.
CPU cores Joshua The pre-release Cyrix III CPUs were based upon a 22 million transistor Joshua core designed by Cyrix.VIA Cyrix III, CPU Scorecard, October 8, 2005. This CPU core was a typical Cyrix design: superscalar with speculative execution and a high IPC rate but rather low clock rates. To emphasize the higher performance of their designs compared to the competitors' offerings, Cyrix used a system with a "P-Rating" higher than the clock rate. The floating point unit of the processor had supposedly been updated from the lacklustre unit in the 6x86/MII series.Loki.Joshua, Ars Technica, accessed May 11, 2007. When the chip reached reviewers, the weighted integer/floating-point performance was found to be fairly low compared to the competition.
Samuel Because the Joshua core was such a mixed result in thermal output, core size, and performance, VIA switched almost immediately to an 11 million transistor Samuel core designed by Centaur Technology.Witheiler, Matthew. The New VIA Cyrix III: The Worlds First 0.15 Micron x86 CPU], Anandtech, January 5, 2001. The Samuel core was a simpler design, being an evolution of the WinChip processors (the unreleased WinChip 4). Samuel was designed for higher clock speeds, with more L1 cache (but no L2), and used smaller manufacturing technology.De Gelas, Johan. Cyrix III, An Alternative Approach , Ace's Hardware, August 6, 2000. While this version of Cyrix III still had sub-par performance compared to the competition from Intel and AMD, it was quite power efficient and consisted of only half the number of transistors of Cyrix's creation.Poluvyalov, Alexander. VIA Cyrix III (Samuel 2) 600 and 667 MHz , Digit Life, accessed May 12, 2007.
VIA dropped the criticized P-Rating with new processors based on the Samuel core, in favor of simply distinguishing them by their actual clock speed.
Samuel 2 The Samuel 2 core is a revision to the Samuel core. The Centaur Technology team added an on-die 64 KiB L2 cache and moved to a 150 nm manufacturing process. These changes improved per-clock performance, reduced power demands, and increased clock speed scalability.
Models & variants ModelCode nameProcess size(μm)Die area(mm²)Number of transistors(millions)Socket(s)PackageCore VoltageTDP(W)Clock speedBus SpeedL1 CacheL2 CachePrice(USD)LaunchPR500Joshua (Gobi)0,1822370CPGA2.222400 MHz133 MHz128 KB256 KB842-22-2000PR5330,1822370CPGA2.223.9433 MHz66 MHz128 KB256 KB99III-466MHzSamuel0,187511.3370CPGA1.80?466 MHz133 MHz128 KBNone?Q2 2000III-500MHz0,187511.3370CPGA1.80?500 MHz100 MHz128 KBNone?Q2 2000III-533MHz0,187511.3370CPGA1.8012533 MHz133 MHz128 KBNone?6-6-2000III-550MHz0,187511.3370CPGA1.8014550 MHz100 MHz128 KBNone?6-6-2000III-600MHz0,187511.3370CPGA1.90 2.015600 MHz100 MHz 133 MHz128 KBNone?6-6-2000III-650MHz0,187511.3370CPGA1.8016650 MHz128 KBNone556-6-2000III-667MHz0,187511.3370CPGA1.8016667 MHz133 MHz128 KBNone606-6-2000III-700MHz0,187511.3370CPGA1.8017700 MHz100 MHz128 KBNone621-19-2001C3-600ASamuel 20,155215.2370CPGA1.6014.5600 MHz100 MHz 133 MHz128 KB64 KB??C3-650A0,155215.2370CPGA1.60650 MHz100 MHz128 KB64 KB??C3-667A0,155215.2370CPGA1.602.5667 MHz133 MHz128 KB64 KB??C3-700A 0,155215.2370CPGA1.603700 MHz100 MHz128 KB64 KB?3-25-2001C3-733A0,155215.2370CPGA1.603733 MHz133 MHz128 KB64 KB?3-25-2001C3-750A0,155215.2370CPGA1.60510.59750 MHz133 MHz128 KB64 KB?5-28-2001C3-800A0,155215.2370CPGA1.60 1.6511.3 13800 MHz100 MHz 133 MHz128 KB64 KB??
Renaming The Cyrix III was later renamed C3, as it was not built upon Cyrix technology at all.
See also List of VIA microprocessors Pentium III VIA C3
References
External links Cyrix III at CPU-World IA-32 implementation: VIA Cyrix III IA-32 implementation: VIA C3 VIA Cyrix III (Samuel 2) 600 and 667 MHz