Editing Cyrix (section)

== Merger with National Semiconductor ==
[[Image:Cyrix M II-433GP - 300MHz CPU 1998 front.jpg|thumb|Cyrix MII 433GP front]]
[[Image:Cyrix M II-433GP - 300MHz CPU 1998 back2.jpg|thumb|Cyrix MII 433GP back]]

In August 1997, while the litigation was still in progress, Cyrix merged with [[National Semiconductor]] (who also already held an Intel cross-license). This provided Cyrix with an extra marketing arm and access to National Semiconductor fabrication plants, which were originally constructed to produce RAM and high-speed telecommunications equipment. Since the manufacture of RAM and CPUs are similar, industry analysts at the time believed the marriage made sense. The IBM manufacturing agreement remained for a while longer, but Cyrix eventually switched all their production over to National's plant. The merger improved Cyrix's financial base and gave them much better access to development facilities.

The merger also resulted in a change of emphasis: National Semiconductor's priority was single-chip budget devices like the [[MediaGX]], rather than higher-performance chips like the 6x86 and MII. Whether National Semiconductor doubted Cyrix's ability to produce high-performance chips or feared competing with Intel at the high end of the market is open to debate. The MediaGX, with no direct competition in the marketplace and with continual pressure on OEMs to release lower-cost PCs, looked like the safer bet.

National Semiconductor ran into financial trouble soon after the Cyrix merger, and these problems hurt Cyrix as well. By 1999, AMD and Intel were leapfrogging one another in clock speeds, reaching 450&nbsp;MHz and beyond, while Cyrix took almost a year to push the MII from PR-300 to PR-333. Neither chip actually ran at 300+&nbsp;MHz. A problem suffered by many of the MII models was that they used a non-standard 83&nbsp;MHz bus. The vast majority of Socket 7 motherboards used a fixed 1/2 divider to clock the [[PCI bus]], normally at 30&nbsp;MHz or 33&nbsp;MHz. With the MII's 83&nbsp;MHz bus, this resulted in the PCI bus running alarmingly out-of-spec at 41.5&nbsp;MHz. At this speed, many PCI devices could become unstable or fail to operate. Some motherboards supported a 1/3 divider, which resulted in the Cyrix PCI bus running at 27.7&nbsp;MHz. This was more stable, but adversely affected system performance. The problem was only fixed in the final few models, which supported a 100&nbsp;MHz bus. Almost all of the 6x86 line produced a large amount of heat, and required quite large (for the time) heatsink/fan combinations to run properly. There was also a problem which made the 6x86 incompatible with the then-popular [[Sound Blaster AWE64]] sound card. Only 32 of its potential 64-voice polyphony could be utilized, as the WaveSynth/WG software synthesizer relied on a Pentium-specific instruction which the 6x86 lacked. Meanwhile, the MediaGX faced pressure from Intel's and AMD's budget chips, which also continued to get less expensive while offering greater performance. Cyrix, whose processors had been considered a performance product in 1996, had fallen to the mid-range, then to the entry level, and then to the fringe of the entry level, and was in danger of completely losing its market.

The last Cyrix-badged microprocessor was the Cyrix MII-433GP which ran at 300&nbsp;MHz (100&nbsp;×&nbsp;3) and performed faster than an AMD&nbsp;K6/2-300 on FPU calculations (as benched with Dr. Hardware). However, this chip was regularly pitted against actual 433&nbsp;MHz processors from other manufacturers. Arguably this made the comparison unfair, even though it was directly invited by Cyrix's own marketing.

National Semiconductor distanced itself from the CPU market, and without direction, the Cyrix engineers left one by one. By the time National Semiconductor sold Cyrix to [[VIA Technologies]], the design team was no more and the market for the MII had disappeared. Via used the Cyrix name on a chip designed by [[Centaur Technology]], since Via believed Cyrix had better name recognition than Centaur, or possibly even VIA.

Cyrix's failure is described by Glenn Henry, CEO of Centaur Technology, thus: "Cyrix had a good product, but they got bought by a 'big smokestack' company and they got bloated. When VIA bought Cyrix, they had 400, and we had 60, and we were turning out more product."<ref>{{Cite web |url=https://archive.linuxgizmos.com/glenn-henry-on-the-isaiah-architecture/ |title=Glenn Henry on the Isaiah architecture |access-date=2016-05-21 |archive-url=https://web.archive.org/web/20160611141856/https://archive.linuxgizmos.com/glenn-henry-on-the-isaiah-architecture/ |archive-date=2016-06-11 |url-status=dead }}</ref>

National Semiconductor retained the MediaGX design for a few more years, renaming it the [[Geode (processor)|Geode]] and hoping to sell it as an integrated processor. They sold the Geode to AMD in 2003.

In June 2006, AMD unveiled the world's lowest-power x86-compatible processor that consumed only 0.9&nbsp;W of power. This processor was based on the Geode core, demonstrating that Cyrix's architectural ingenuity still survived.