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Cyrix 6x86 & 6x86+

The Cyrix 6x86+ : Image courtesy of Cyrix Corporation

The Cyrix 6x86 range was introduced in 1995 as a rival to the Intel Pentium. Pin Compatible with the Pentium's Socket 5/7 layout the Cyrix 6x86 processor offered a powerful "drop in" alternative to its 5th generation rivals. The Cyrix 6x86 range possessed the most powerful processor core of any "x86" processor of its generation, leading to Cyrix using the same controversial P Rating system as the AMD K5. Unfortunatly, like the K5 the 6x86 processor also possessed a very slow floating point math capability and so was a very poor games and 3D performer.

The Cyrix 6x86 processor suffered severe heat dissipation problems in early models, and some were destroyed by overheating whilst running. This problem was cured with the release of the 6x86L which had a lower heat output than the ordinary 6x86, but still required the use of a heavy duty heat sink and fan. The 6x86 processor also suffered a number of compatability problems, which did not help to enhance its reputation.

The 6x86 PR200 (150 Mhz) processor also saw the introduction of non-standard (ie; not used by Intel) bus speeds. The PR200 chip uses a bus speed of 75 MHz, thus making the number of motherboards which support it very few.

Despite all the problems listed above the Cyrix 6x86 is not a bad processor, and we at the Processor Emporium have an affection for this little chip. In its day, its integer performance was astonishing and made it great value for money. If used in the correct way, with adequate cooling and not used for demanding graphics, the Cyrix 6x86 is a very good processor, especially in its higher speed varients (PR166 & PR200). The lower speed chips like the lower powered Pentium and K5 processors are now a bit long in the tooth, but still would form the basis of a great Linux machine. The Processor Emporium would recommend this as a good second hand alternative to the Pentium, but would advise caution as the prices of used AMD K6 processors are falling fast and would only recommend the 6x86 if it were significantly cheaper than the K6.

Cyrix 6x86 Processor, Technical Data

Processor Clock Speed Bus Speed Clock Muiltiplier
PR 120+ 100 MHz 50 MHz 2x
PR 133+ 110 MHz 55 MHz 2x
PR 150+ 120 MHz 60 MHz 2x
PR 166+ 133 MHz 66 MHz 2x
PR 200+ 150 MHz 75 MHz * 2x
* denotes non-standard bus speed

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