A CPU History

Posted Mar 23, 2001 | by David Risley  


Cyrix 6×86 Series (1995)


Cyrix, by this time, was a major player in the alternative processor market. They had been around since 1992, with their release of the 486SLC. By 1995, they had their own 5×86 processor and it was considered the only real competition to the AMD counterpart. But, they released their 6×86 in 1995. It was designed to go head to head with Intel’s Pentium processor. Dubbed “M1″, the chip contained two super-pipelined integer units, an on-die FPU, and 16 KB of write-back cache. It used many of the same techniques internally as the Intel and AMD chips to increase performance. Like AMD beginning with their K5 (see below), Cyrix used the P-rating system. It came in PR-120, 133, 150, 166 and 200 versions. Each rating had a “+” after it, indicating that it performed better than the corresponding Pentium. But, did it?


Cyrix had had a reputation for lagging in the area of performance, and the M1 was not an exception. The chip used a weaker FPU than both AMD and Intel, meaning it could not keep up with the competition in areas such as 3D gaming or other math-intensive software. On top of that, the chip had a reputation for running hot. Users had to get CPU fans that could keep these hot processors cool enough to run stably. Cyrix tried to combat this issue with the 6×86L processor. This “low power” processor made use of a split voltage (3.3 volts for I/O and 2.8 volts internally).


MediaGX (1996)


MediaGX was Cyrix’s answer to low-cost entry level PC’s. Making use of a standard x86 processor core, the chip lowered the cost of PCs using it by integrating many of the common PC components into the chip itself. MediaGX had integrated audio and video circuitry, as well as circuitry to handle many of the common tasks normally handled by chips on the motherboard itself. The CPU spoke directly to a PCI bus and DRAM memory, and the video was rather high-quality SVGA (for the time). It could support up to 128 MB of EDO RAM in 4 separate memory banks, and the video sub-system could support resolutions of up to 1280×1024x8 or 1024×768x16.


The integration of MediaGX was actually spanned across two chips: the processor itself and the MediaGX Cx5510. The chip requires a specially designed motherboard. It is not Socket 7 compatible. As a result, it is really an outsider in relation to the other processors we were discussing, but being that it was on the timetrack of history for CPUs, it bears mentioning.

Which Of These Traits Applies To YOUR Computing Life?...

12 Responses to “A CPU History”

  1. Jagath says:

    Your Notes are very clear and Excelent. If you can update to current, it is very good.

    Thank you

  2. kgaugelo says:

    Your notes have helped me a lot about something i’ve been looking for in the past week.your Your notes are excelent thanx

  3. Woogle says:

    Just to point out that you state the 80186 never made it into a personal computer, however i owned a 186 system around 1992 that was made my Research Machines.
    Just thought you would like to know.

    • archetype says:

      There was also a Tandy / Radio Shack PC that used an 80186. Just one model that didn’t last for more than a year. Their usual black and silver case. I can’t swear that it was 100% compatible with the usual instruction sets that software depended on.

      • Hugh Wyn Griffith says:

        That Tandy 186 was the Tandy 2000 and its graphics were not 100% compatible with Windows much to the distress of users (I was one when I bought my first “almost-PC” in the UK back in the ’90’s). This caused a lot of ill feeling between users and Tandy. The Users Group launched a monthly called “Orphans” and hated Ed Juge (who died recently) the then CEO of Tandy for not providing any support.

        I was amused a few years ago when Googling on Tandy 2000 to pull up a full page advert for it from one of the well known magazines at that time in which Bill Gates lauded it saying how much his programmers depended on it for its performance! Might explain some of Windows problems if they were using a non-conforming PC !

  4. Chris says:

    The 5×86 was not AMD’s answer to the Pentium, the P5 was. The 5×86 was made to offer a greater performance boost to the millions of 486 PC’s out there, as it would work in (almost) any 486 motherboard with a socketed CPU or overdrive socket.

  5. darrel says:

    Chris, It doesn’t say it was AMD’s answer. It was their “competitive response to Intel’s Pentium-class processor”
    on a 486 motherboard.

    Also, not mentioned is why Intel went from a number designation to a name title, the number, was actually the stock number. As I was told by a Intel Rep. at a Comdex show (Vegas) ‘94-’95. As Intel tried to sue AMD for copy right infringement. Like a fragrance, you can’t CR. the recipe only the name. They lost on the grounds, you can’t copy right a stock number (80486)! So they, Intel started using name designation (Pentium). As well as AMD did the same.

  6. Stuart says:

    This is great, im supposed to be at work, but im reading this, just spent quite a while reading it. Its very interesting, Thank You

  7. Bill Buchanan says:

    Correction to information provided on the Intel 80186 (1980).
    This Processor was used in one desk top system but the system did not sell well. The company was Tandy and the model was Tandy 2000. There is a very good page at: http://www.old-computers.com/museum/computer.asp?c=1219 covering the processor.

  8. Mick Russom says:

    Acorn’s Master 512 PC had a 10MHz 80186 CPU which ran MS-DOS and GEM. I would say this qualifies it as a “PC” running a 80186 running MS-DOS.

  9. Sandy Jelusic says:

    I have at home an pc desktop powered by an 8088 at 3.5 mhz with turbo mode, black-yellow monitor, 20mb disk and only 5.25” floppy. As for dos I think it’s ibm-dos. Not really certain.

  10. manzoor says:

    Very knowledgeful. Please update with latest changes.

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