Cyrix was a CPU manufacturer that began in 1988 in Richardson, Texas as a specialist supplier of high-performance math coprocessors for 286 and 386 systems. The company was founded by former Texas Instruments staff members and had a long but troubled relationship with TI throughout its history.

Cyrix founder Jerry Rogers aggressively recruited engineers and pushed them, eventually assembling a small but efficient design team of 30 people.


The first Cyrix product for the personal computer market was a x87 compatible FPU coprocessor. The Cyrix FasMath 83D87 and 83S87 were introduced in 1989. The FasMath was the fastest 386-compatible coprocessor and provided up to 50% more performance than the Intel 80387. Cyrix FasMath 82S87, a 80287-compatible chip was developed from the Cyrix 83D87 and has been available since 1991.
Cyrix FasMath

Its early CPU products included the 486SLC and 486DLC, released in 1992, which, despite their names, were pin-compatible with the 386SX and DX, respectively. While they added an on-chip L1 cache and the 486 instruction set, performance-wise they were somewhere between the 386 and the 486. The chips were mostly used as upgrades by end users looking to improve performance of an aging 386 and especially by dealers, who by changing the CPU could turn slow-selling 386 boards into budget 486 boards. The chips were widely criticized in product reviews for not offering the performance suggested by their names, and for the confusion caused by their naming similarity with Intel's SL line and IBM's SLC line of CPUs, neither of which was related to Cyrix's SLC. The chips did see use in very low-cost PC clones and in laptops.

Cyrix would later release the Cyrix 486SRX2 and 486DRX2, which were essentially clock-doubled versions of the SLC and DLC, marketed exclusively to consumers as 386-to-486 upgrades.

Eventually Cyrix was able to release a 486 that was pin-compatible with its Intel counterparts. However, the chips were later to market than AMD's 486s and benchmarked slightly slower than AMD and Intel counterparts, which relegated them to the budget and upgrade market. While AMD had been able to sell some of its 486s to large OEMs, notably Acer and Compaq, Cyrix had not. The Cyrix chips did gain some following with upgraders, as their 50-, 66- and 80 MHz 486 CPUs ran at 5 volts, rather than the 3.3 volts used by AMD, making the Cyrix chips usable as upgrades in early 486 motherboards.

In 1995, with its Pentium clone not yet ready to ship, Cyrix repeated its own history and released the Cx5x86, which plugged into a 486 socket, ran at 100, 120 or 133 MHz, and yielded performance comparable to that of a Pentium running at 75 MHz. While AMD's Am5x86 was little more than a clock-quadrupled 486 with a new name, Cyrix's 5x86 implemented some Pentium-like features.
Cyrix MediaGX

Later in 1995 Cyrix released its best-known chip, the 6x86 (M1), this processor continued the Cyrix tradition of making faster replacements for Intel designed sockets, however the 6x86 was the star performer in the range, giving a tangible performance boost over the Intel "equivalent". 6x86 processors were given names such as P166+ indicating a performance better than a Pentium 166MHz processor, in fact the 6x86 processor was clocked at a significantly lower speed than the Pentium part it outperformed. Initially Cyrix tried to charge a premium for its extra performance, but the 6x86's math coprocessor was not as fast as that in the Intel Pentium, the main difference being not one of actual computing performance on the coprocessor, but the lack of instruction pipelining. Due to the increasing popularity of first-person 3D games, Cyrix was forced to lower its prices. While the 6x86 quickly gained a following among computer enthusiasts and independent computer shops, unlike AMD its chips had yet to be used by a major OEM customer.

The later 6x86L was a revised 6x86 that consumed less power, and the 6x86MX (M2) added MMX instructions and a larger L1 cache. The MII, based on the 6x86MX design, was little more than a name change intended to help the chip compete better with the Pentium II.

In 1996 Cyrix released the MediaGX CPU, which integrated all of the major discrete components of a PC, including sound and video, onto one 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 successful. The MediaGX led to Cyrix's first big win, when Compaq used it in its lowest-priced Presario 2100 and 2200 computer. 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.

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


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