In a more modern context, the complex variable length encoding used by some of the typical CISC architectures makes it complicated, but still feasible, to build a superscalar implementation of a CISC programming model directly ; the in-order superscalar original Pentium and the out-of-order superscalar Cyrix 6x86 are well known examples of this.

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.

Because the 6x86 was more efficient on an instructions-per-cycle basis than Intel's Pentium, and because Cyrix sometimes used a faster bus speed than either Intel or AMD, Cyrix and competitor AMD co-developed the controversial PR system in an effort to compare its products more favorably with Intel's.

In the early days, Cyrix mostly used Texas Instruments production facilities and SGS Thomson ( now STMicroelectronics ).

While some in the industry speculated this would lead to IBM using 6x86 CPUs extensively in its product line and improve Cyrix's reputation, IBM continued to mostly use Intel CPUs, and to a lesser extent, AMD CPUs, in the majority of its products and only used the Cyrix designs in a few budget models, mostly sold outside of the United States.

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.

Additionally, the acquisition of Cyrix's intellectual property and agreements would be used by VIA to defend itself from its own legal troubles with Intel, even after VIA Technologies stopped using the Cyrix name.

The Cyrix 5x86 processor, codename " M1sc ", was based on a scaled-down version of the " M1 " core used in the Cyrix 6x86, which provided 80 % of the performance for a 50 % decrease in transistors over the 6x86 design.

The Cyrix 5x86 design, however, should not be confused with the similarly named AMD Am5x86 which was essentially a fast 486 ( not an all-new design like the Cyrix part ) but which had broadly similar performance, used the same Socket 3, and was introduced at the end of the same year.

Processors that used Socket 7 are the AMD K5 and K6, the Cyrix 6x86 and 6x86MX, the IDT WinChip, the Intel P5 Pentium ( 2. 5 – 3. 5 V, 75 – 200 MHz ), the Pentium MMX ( 166 – 233 MHz ), and the Rise Technology mP6.

Super Socket was used by AMD K6-2 and K6-III processors, and some of the final Cyrix M-II processors.

Socket 370 was originally used for the Intel Celeron, but later became the socket / platform for the Coppermine and Tualatin Pentium III processors, as well as the Via-Cyrix Cyrix III, later renamed the VIA C3.

Although VIA initially branded processors as " Cyrix ," the company initially used technology similar to WinChip with its Cyrix III line.

Since the f00f bug has become common knowledge, the term is sometimes used to describe similar hardware design flaws such as the Cyrix coma bug.

This version came with a card that featured a Cyrix CX486 DX2 / 66 80486 processor and a single SIMM RAM slot that used the same type of RAM to that in the Power Mac itself, and could hold up to 32mb of RAM, a Creative Technology Vibra 16 sound chipset, and also sported standard PC VGA and joystick ports.

* Performance Rating, modeling scheme used by AMD and Cyrix to reflect the relative performance usually compared to competing products.

Later that year, Cyrix also adopted the PR system for its 6x86 and 6x86MX line of processors.

With the demise of the Cyrix MII ( a renamed 6x86MX ) from the market in 1999, the PR system appeared to be dead, but AMD revived it in 2001 with the introduction of its Athlon XP line of processors.

It also adopted the performance rating concept, similar to how AMD and Cyrix marketed their processors.

" Cyrix Doubles x86 Performance with M2 ".

The first highly ( or tightly ) pipelined x86 implementations, the 486 designs from Intel, AMD, Cyrix, and IBM, supported every instruction that their predecessors did, but achieved maximum efficiency only on a fairly simple x86 subset that was only a little more than a typical RISC instruction set ( i. e. without typical RISC load-store limitations ).

The acquisition of Cyrix also carried with it a business obligation as well as technical constraints to use IBM microelectronics division to fabricate the Cyrix chips, while National Semiconductor had plans to transfer their fabrication to its South Portland fab.

Cyrix had always been a fabless company: Cyrix designed and sold their own chips, but contracted the actual semiconductor manufacturing to an outside foundry.

But the final settlement was out of court: Intel agreed that Cyrix had the right to produce their own x86 designs in any foundry that happened to already hold an Intel license.

Both firms gained out of this: Cyrix could carry on having their CPUs made by Texas Instruments, SGS Thomson, or IBM, all holders of Intel cross-licenses ; Intel avoided a potentially embarrassing loss.

The follow-on 1997 Cyrix-Intel litigation was the reverse: instead of Intel claiming that Cyrix 486 chips violated their patents, now Cyrix claimed that Intel's Pentium Pro and Pentium II violated Cyrix patents — in particular, power management and register renaming techniques.

The IBM manufacturing agreement remained for a while longer, but Cyrix eventually switched all their production over to National's plant.

Later, they also released their own version of the chip, the TI486SXLC which featured 8kB internal cache vs 1kB in the original Cyrix design.

The FPU in the 6x86 was largely the same circuitry that was developed for Cyrix's earlier high performance 8087 / 80287 / 80387-compatible coprocessors, which was very fast for its time — the Cyrix FPU was much faster than the 80387, and even the 80486 FPU.

Similar to the AMD K5, the Cyrix 6x86 was a design far more focused on integer per-clock performance than clock scalability, something that proved to be a strategic mistake.

The 6x86's and MII's old generation " 486 class " floating point unit combined with an integer section that was at best on-par with the newer P6 and K6 chips meant that Cyrix could no longer compete in performance.

These included Cyrix which marketed its FasMath series as higher performance but fully x87 compatible, and Weitek which offered a high-performance but not fully x87 compatible series of coprocessors.

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.

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.

Cyrix, whose product had been considered a performance product in 1996, had fallen to the mid-range, then the entry level, and to the fringe of the entry level and was in danger of completely losing its market.

With better performance in most applications than an Intel Pentium processor at 75 MHz, the Cyrix Cx5x86 filled a gap by providing a medium-performance processor option for 486 Socket 3 motherboards ( which are incapable of handling Intel's Pentium CPUs, apart from the Pentium Overdrive ).

While competing 486 chips, such as those from Cyrix, benchmarked lower than the equivalent Intel chip, AMD's 486 matched Intel's performance on a clock-for-clock basis.

Its floating point performance was well below that of the Pentium, being similar to the Cyrix 6x86.

Mainboards using this chipset and equipped with CPUs such as the Intel 80486DX4, AMD 5x86 or Cyrix Cx5x86 processors had performance and compatibility comparable with early Intel Pentium systems in addition to a lower price.

Additionally, while the K5's floating point performance was better than that of the Cyrix 6x86, it was weaker than that of the Pentium.

The Cyrix Cx486SLC was Cyrix's first CPU offering, released after years of selling coprocessors that competed with Intel's units and offered better performance at a comparable or lower price.

The Socket AM2, renamed from Socket M2 ( to prevent using the same name as Cyrix MII processors ), is a CPU socket designed by AMD for desktop processors, including the performance, mainstream and value segments.

* CPU Extender-Allows you to detect CPU type and performance from Intel 80486 and later processors, as well as AMD and Cyrix processors.