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 Cyrix 6x86-P150+GP
Cyrix 6x86-P150+GP, no Voltage Markings
Cyrix 6x86-P150+GP w/ Capacitors
Cyrix 6x86-P166+GP 3.53V
Cyrix 6x86-P166+GP
Cyrix 6x86-PR166+GP
Cyrix 6x86L-P150+GP
Cyrix 6x86L-PR166+GP
Cyrix 6x86L-PR200+GP
Cyrix 6x86L-PR200+GP, Variant
Cyrix 6x86MX-PR166
Cyrix 6x86MX-PR200, 75 MHz Bus
Cyrix 6x86MX-PR200, 66 MHz Bus
Cyrix 6x86MX-PR233
Cyrix M II-233GP, 66 MHz Bus, Dark
Cyrix M II-266GP, 66 MHz Bus
Cyrix M II-300GP, 66 MHz Bus
Cyrix M II-300GP, 66 MHz Bus, Dark
Cyrix M II-300GP, 75 MHz Bus
Cyrix M II-333GP, 66 MHz Bus, Silver
Cyrix M II-333GP, 75 MHz Bus
Cyrix M II-333GP, 83 MHz Bus, Engineering Sample
Cyrix M II-366GP, 100 MHz Bus
Cyrix M II-400GP, 95 MHz Bus
Cyrix Gx86 GX-133BP
Cyrix MediaGX GX-120BP
Cyrix MediaGX GX-133BP
Cyrix MediaGX GX-150BP
Cyrix MediaGX GXI-166BP
Cyrix MediaGX GXI-180BP
Cyrix MediaGX GXI-180BP (silver)
Cyrix MediaGX GXm-233BP
Cyrix MediaGX GXm-266BP
Cyrix MediaGX GXm-180GP
Cyrix MediaGX GXm-200GP
Cyrix MediaGX GXm-200GP 85C
Cyrix MediaGX GXm-233GP
Cyrix MediaGX GXm-266GP
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» Cyrix overview
» all 686 chips
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The Cyrix 6x86 Processor
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 | | 1995 marketing logo |
Cyrix entered the fifth generation processor market with the 6x86 processor, formerly projected as the M1. As a successful and cheaper (often less than half the cost) alternative to the Intel Pentium, it is pin- and voltage-compatible with it. Cyrix gave it the 6x86 name in reference to some of its more advanced features, which it calls "sixth generation". In reality, the processor is comparable in power and architecture to the fifth-generation Pentium.
The 6x86 is not a Pentium clone. Clones are exact or near-exact copies, usually being reversed engineered or based on licensed code. The 6x86 is based on an original Cyrix design. It incorporates several advanced architectural features that allow it to outperform a Pentium of equal clock speed. For this reason Cyrix helped invent the "P-Rating" system. This was an advantage to help people make a valid comparism but also caused some confusion when setting the appropriate clock speed on the motherboard.
The Cyrix 6x86 range has the most powerful processor core of any x86 processor of its generation. Unfortunately, like the AMD K5, it also has a very slow floating point math capability and so was a very poor games and 3D performer.
The processor is designed for Socket 7 and is available in several clock speeds, some of them rather unusual. The 6x86 PR200 (150 Mhz) processor introduced non-standard bus speeds up to 75 MHz - many motherboards and PCI cards did not support this speeds: Since the PCI bus runs at half of the mainboard bus speed, you are increasing the PCI bus to 37.5 MHz with a bus speed of 75 MHz. Several PCI cards, especially some graphics cards, did not run correctly with this overclocked bus.
References:
Cyrix 6x86 Processor Brief
Cyrix 6x86 Processor FAQ
Cyrix Press Releases |
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| The earlier versions of the 6x86 had problems with heat and power consumption. Responding to customer complaints, Cyrix came out with a lower powered version called the 6x86L. This processor reduces power consumption by 25% or more compared to the original 6x86. It uses a smaller, 0.35 micron circuit size and split voltage much like the Pentium MMX (3.3V external, 2.8V internal). |
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The Cyrix 6x86MX Processor
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The successor to the 6x86 and 6x86L is the 6x86MX (M2), introduced May 30, 1997 and intended to compete with AMD's K6 and Intel's Pentium MMX. The 6x86MX is an evolutionary step from the 6x86 and is very similar to it in internal function.
The 6x86MX supports the MMX extension and also features several other improvements over the original 6x86 chip. The internal cache was increased from 16 to 64 KB, a 256 byte additional pre-cache was added to help improve efficiency in how the regular level 1 cache is operated, the Branch Prediction was improved and the internals of the chip have been optimized for 32-bit operation.
References:
Cyrix 6x86 Processor FAQ
Cyrix Press Releases
Cyrix 6x86MX Press Tour |
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The Cyrix MII Processor
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After Cyrix was purchased by National Semiconductor in 1997 they terminated their foundry agreement with IBM. National fabricated their own chips and the 6x86MX was re-named MII. Compared to early 6x86MX CPUs the MII had some enhancements to its processor core. Heat output was reduced allowing it to rise to clock speeds over 220MHz. The MII also required non-standard bus speeds at 75 or 83MHz on socket 7 boards and therefore had some troubles with stability.
Reference:
Cyrix M2 Processor FAQ |
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The Cyrix MediaGX Processor
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In 1996 Cyrix released the MediaGX CPU, which integrated all of the major discrete components of a PC, including memory controller, graphics, sound and PCI controller, onto a single chip. Initially based on the old 5x86 technology and running at 120 or 133 MHz, its performance was widely criticized but its low price made it quite successful. Though it required a special motherboard and was not pin compatible with the Pentium, it was the cheapest route into a Pentium class system available on the market. Later versions of the MediaGX ran at speeds of up to 333 MHz and added MMX support. A second chip was added to extend its video capabilities.
The MediaGX led to Cyrix's first big win, when Compaq used it in its lowest-priced Presario computers. This led to further MediaGX sales to Packard Bell and also seemed to give Cyrix legitimacy, as 6x86 sales to Packard Bell and eMachines quickly followed.
But because it seemed to have so much potential in the low-cost market, it dragged Cyrix's attention away from the main market - high-performance desktop parts - and attracted the interest of other companies, notably National Semiconductor, which bought Cyrix in July 1997 largely on the strength of the MediaGX design, and over the next year or so proceeded to mismanage the company into oblivion.
References:
Official Announcement
MediaGX Processor FAQ
Press Tour
Architecture Overview |
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