Cyrix CPUs

Intel enjoyed a comfortable position as the PC processor manufacturer of choice throughout the 1990s. Dating from the time of their 486 line of processors, in 1989, it was Cyrix, together with fellow long-time Intel cloner Advanced Micro Devices (AMD), who have posed the most serious threat to Intel’s dominance.

Founded in 1988 by ex-Texas Instruments staff, Cyrix began as a specialist supplier of high-performance math co-processors for Intel 286 and 386 systems. In the early 1990s both Cyrix and AMD made their own versions of Intel’s 486DX, but their products became better known with their 486DX2 clones, one copying the 486DX2-66 (introduced by Intel in 1992) and another upping the ante to 80MHz for internal speed. The 486DX2-80 was based on a 40MHz system bus, and unlike the Intel DX2 chips (which ran hot at 5V) it ran at the cooler 3.3V. This was in part due to the power management features offered by the Cyrix chips, an innovation on which Intel would follow suit a couple of year later. Clock-tripled versions of their 40MHz 486 processors running at 120MHz were subsequently introduced.

Although Intel stopped improving the 486 with the DX4-100, AMD and Cyrix kept going. In 1995, with its Pentium clone not yet ready to ship, Cyrix released the Cyrix 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. The chip included a 64-bit internal bus, a six-stage pipeline (as opposed to the DX4’s five-stage pipeline), and branch-prediction technology to improve the speed of instruction execution. It’s important to remember, however, that the Cyrix 5×86 appeared after Intel had introduced the Pentium, so these features were more useful in upgrading 486s than in pioneering new systems. Later in 1995 Cyrix released its best-known chip, the 6×86, which was the company’s first CPU to exceed the performance of the Intel chip it was intended to compete against.

In the post-Pentium era, Cyrix continued to meet with reasonable levels of market acceptance, especially in the low-cost, basic PC market segment. With Intel now concentrating on its Slot 1 and Slot 2 designs, the target for its competitors was to match the performance of Intel’s new designs as they emerge, without having to adopt the new processor interface technologies. As a consequence the lifespan of the Socket 7 form factor was considerably extended, with both motherboard and chipset manufacturers co-operating with Intel’s competitors to allow Socket 7 based systems to offer advanced features such as 100MHz frontside bus and AGP support.

Unlike AMD, Cyrix had never manufactured or sold Intel designs under a negotiated license. Cyrix’s designs were the result of meticulous in-house reverse-engineering. So while AMD’s 386s and even 486s had some Intel-written microcode software, Cyrix’s designs were completely independent. Focused on removing potential competitors, Intel spent many years in legal battles with Cyrix, claiming that the Cyrix 486 violated Intel’s patents. In August 1997, while the litigation was still in progress, Cyrix merged with National Semiconductor (who also already held an Intel cross-license). National Semiconductor ran into financial difficulties soon after the Cyrix merger, and these were subsequently to hurt Cyrix as well.

Mid-1999 saw some important developments, which were to have a significant bearing on the competitive position in the processor market over the coming years. In August, Cyrix finally bowed out of the PC desktop business when National Semiconductor sold the rights to its x86 CPUs to Taiwan-based chipset manufacturer VIA Technologies. The highly integrated MediaGX product range remained with National Semiconductor – to be part of the new Geode family of system-on-a-chip solutions the company is developing for the client devices market.

A matter of days later, VIA announced its intention to purchase IDT’s Centaur Technology subsidiary – responsible for the design and production of its WinChip x86 range of processors. It was unclear if these moves signalled VIA’s intention to become a serious competitor in the CPU market, or whether its ultimate goal was to compete with National Semiconductor in the system-on-a-chip market. Hitherto the chipset makers had lacked any x86 design technology to enable them to take the trend for low-cost chipsets incorporating increasing levels of functionality on a single chip to its logical conclusion.

Although the company was short-lived and the brand name is no longer actively used by its current owner, Cyrix’s legacy is an important one. Its competition with rival chipmaker AMD created the market for budget CPUs. This led to a lowering of PC prices and, ultimately, to Intel’s decision to produce its Celeron line of budget processors and to cut the prices of its faster processors more quickly in order to remain competitive.

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