Cyrix
Cyrix Corporation was a microprocessor developer that was founded in 1988 in Richardson, Texas, as a specialist supplier of floating point units for 286 and 386 microprocessors. The company was founded by Tom Brightman and Jerry Rogers. Jerry Rogers was also serving as the company Chief Executive Officer and president up until December 9, 1996, when he stepped down from this role, but remained on the Board of Directors.
In 1992, Cyrix introduced its own i386 compatible processors, the 486SLC and 486DLC. These had higher performance than the Intel parts, but a lower price. They were primarily marketed to users looking to upgrade existing machines. Their release sparked a lengthy series of lawsuits with Intel while their foundry partner IBM was releasing the same designs under their own branding.
The combination of these events led Cyrix to begin losing money, and the company merged with National Semiconductor on 11 November 1997. National released Cyrix's latest designs under the MediaGX name and then an updated version as Geode in 1999. National sold the line to AMD in August 2003 where it was known as Geode. The line was discontinued in 2019.
History
At the end of March in 1992, the Cyrix Cx486SLC was released. It was a x86 microprocessor that was pin-compatible with the 386SX and made for notebook computer applications. Following up shortly after in June 1992, the Cx486DLC was released, a desktop version of the SLC that was pin-compatible with the 386DX.Products
Cyrix FasMath coprocessors
The first Cyrix product for the personal computer market was a x87 compatible FPU coprocessor. The Cyrix FasMath 83D87 and 83S87 were introduced in November 1989. The 83D87 was pin compatible with the Intel 80387, while the 83S87 was pin compatible with the 80387SX. Both provided up to 50% more performance, and additionally they had lower power consumption when idle, due to a low power operation. Upon release the 83S87 cost $506 for a 16-MHz version and $556 for a 20-MHz version. The Cyrix FasMath 82S87, a 80287-compatible chip, was developed from the Cyrix 83D87 and has been available since 1991.Image:KL Cyrix 486DRx2.jpg|thumb|right|150px|Cyrix Cx486DRx² microprocessor
486
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. Unlike the SLC/DLC, these chips contained internal cache coherency circuitry which made the chips compatible with older 386 motherboards that did not have extra circuitry or BIOS routines to keep the cache current.
Eventually, Cyrix was able to release the Cyrix Cx486S and later Cyrix Cx486DX that was pin-compatible with its Intel 486 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 V, rather than the 3.3 V used by AMD, making the Cyrix chips usable as upgrades in early 486 motherboards.
Cyrix 5x86
In 1995, with its Pentium clone not yet ready to ship, Cyrix repeated its own history and released the Cyrix Cx5x86, which plugged into a 3.3V 486 socket, ran at 80, 100, 120, or 133 MHz, and yielded performance comparable to that of a Pentium running at 75 MHz. Cyrix 5x86 was a cost-reduced version of the flagship 6x86. Like Intel's Pentium Overdrive, the Cyrix 5x86 used a 32-bit external data bus.While AMD's Am5x86 was little more than a clock-quadrupled 486 with a new name, Cyrix's 5x86 implemented some Pentium-like features.
Image:Cyrix 6x86-P166.jpg|right|thumb|180px|Cyrix 6x86-P166
Cyrix 6x86
Later in 1995, Cyrix released its best-known chip, the Cyrix 6x86. 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 claimed performance boost over the Intel "equivalent". 6x86 processors were given names such as P166+ indicating a performance better than a Pentium 166 MHz processor. In fact, the 6x86 processor was clocked at a significantly lower speed than the Pentium counterpart it outperformed. Initially, Cyrix tried to charge a premium for the Cyrix-claimed extra performance, but the 6x86's math coprocessor was not as fast as that in the Intel Pentium. The main difference was not one of actual computing performance on the coprocessor, but a 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 game in question causing most problems for performance was Id Software's Quake. Unlike previous 3D games, Quake used the pipelined Pentium FPU to do perspective correction calculations in the background while texture mapping, effectively doing two tasks at once. This would not have been a big problem for the 6x86 if, by that time, Quake had a fallback to do perspective correction without the FPU as in, for example, the game Descent. However, id Software chose not to include this. Quake also lacked the option to disable perspective correction, thus eliminating that potential speed boost for FPU-weak CPUs. This potential speed boost would have benefited not just Cyrix's users, but also users of AMD's K5 and especially of the 486. Quakes optimization for the Pentium went beyond FPU usage and catered to a number of other architectural quirks specific to the Pentium, further hindering performance of other CPUs even outside FPU operations. This bias in favor of the Pentium served to boost the popularity of Intel's Pentium CPUs amongst the computer game community.Cyrix 6x86L and 6x86MX
The later 6x86L was a revised 6x86 that consumed less power, and the 6x86MX added MMX instructions and a larger L1 cache. The Cyrix MII, based on the 6x86MX design, was little more than a name change intended to help the chip compete better with the Pentium II.Image:KL Cyrix MediaGXm PGA.jpg|thumb|right|180px|Cyrix MediaGX
Cyrix MediaGX
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, with Compaq using it in its lowest-priced Presario 2100 and 2200 computers. This led to further MediaGX sales to Packard Bell and also seemed to give Cyrix legitimacy, with 6x86 sales to both Packard Bell and eMachines following.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.
Cyrix Media GXi, Jedi, and Gobi Cayenne
Cyrix developed the Cayenne core as an evolution of the 6x86MX/MII processor, with dual issue FPU, support for 3DNow instructions and a 256 KB, 8-way associative, on-die L2 cache. This core was intended to be used in multiple products, including a successor to the MediaGX chip, a product codenamed Jedi which was to be a Socket 7 compatible processor which was later cancelled in favor of a Socket 370 compatible processor codenamed Gobi.The Media GXi implementation was released in February 1997; intended for the mobile computing market, it had clock speeds of 120 Mhz to 180 Mhz, and had integrated graphics and audio controllers, making it useful for compact notebook computers. Later that year, Cyrix was acquired by National Semiconductor.
Cyrix M3 Jalapeno
This was a completely new core with a dual issue FPU, register renaming and out-of-order execution based on an 11-stage pipeline and 8-way associative, 8-way interleaved fully pipelined 256K L2 cache operating at core frequency.Jalapeño's new floating point unit had dual independent FPU/MMX units and included both a fully pipelined, independent x87 adder and x87 multiplier. The Jalapeño design facilitated close integration between the core and the advanced 3D graphics engine, which was one of the first graphics subsystems to utilize a dual-issue FPU. The dual FPUs supported execution of both MMX and 3DNow instructions.
Jalapeno had an on-die memory controller based on RAMBUS technology capable of 3.2 GB/s to reduce memory latency and an integrated on-board 3D graphics which purportedly could process up to 3 million polygons per second and 266 million pixels per second based on a 233 Mhz clock. The on-die graphics had access to the L2 cache of the CPU to store textures. The design's initial clock speed target was 600-800 Mhz with headroom to scale to 1 Ghz and beyond. It was due to begin production in Q4 1999 and launch in the year 2000 on a 0.18 micron process with a die size of 110–120 mm2.
It is unclear how advanced development on this core was when Cyrix was acquired from National Semiconductor by VIA Technologies and the project discontinued. VIA did, however, continue producing late-generation Cyrix chips under the name VIA Cyrix III.