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As the 32-bit Intel Architecture became the dominant computing platform during the 1980s and 1990s, multiple companies have tried to build microprocessors that are compatible with that Intel instruction set architecture. Most of these companies were not successful in the mainstream computing market. So far, only AMD has had any market presence in the computing market for more than a couple of product generations. Cyrix was successful during the 386 and 486 generations of products but did not do well after the Pentium was introduced.
List of former IA-32 compatible microprocessor vendors:
The Cyrix 6x86 is a line of sixth-generation, 32-bit x86 microprocessors designed and released by Cyrix in 1995. Cyrix, being a fabless company, had the chips manufactured by IBM and SGS-Thomson. The 6x86 was made as a direct competitor to Intel's Pentium microprocessor line, and was pin compatible. During the 6x86's development, the majority of applications performed almost entirely integer operations. The designers foresaw that future applications would most likely maintain this instruction focus. So, to optimize the chip's performance for what they believed to be the most likely application of the CPU, the integer execution resources received most of the transistor budget. This would later prove to be a strategic mistake, as the popularity of the P5 Pentium caused many software developers to hand-optimize code in assembly language, to take advantage of the P5 Pentium's tightly pipelined and lower latency FPU. For example, the highly anticipated first-person shooter Quake used highly optimized assembly code designed almost entirely around the P5 Pentium's FPU. As a result, the P5 Pentium significantly outperformed other CPUs in the game.
The Intel 80286 is a 16-bit microprocessor that was introduced on February 1, 1982. It was the first 8086-based CPU with separate, non-multiplexed address and data buses and also the first with memory management and wide protection abilities. The 80286 used approximately 134,000 transistors in its original nMOS (HMOS) incarnation and, just like the contemporary 80186, it can correctly execute most software written for the earlier Intel 8086 and 8088 processors.
The 8086 is a 16-bit microprocessor chip designed by Intel between early 1976 and June 8, 1978, when it was released. The Intel 8088, released July 1, 1979, is a slightly modified chip with an external 8-bit data bus, and is notable as the processor used in the original IBM PC design.
The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor designed by Intel. The first pre-production samples of the 386 were released to select developers in 1985, while mass production commenced in 1986. The processor was a significant evolution in the x86 architecture, extending a long line of processors that stretched back to the Intel 8008. The 386 was the central processing unit (CPU) of many workstations and high-end personal computers of the time. The 386 began to fall out of public use starting with the release of the i486 processor in 1989, while in embedded systems the 386 remained in widespread use until Intel finally discontinued it in 2007.
The Intel 486, officially named i486 and also known as 80486, is a microprocessor. It is a higher-performance follow-up to the Intel 386. The i486 was introduced in 1989. It represents the fourth generation of binary compatible CPUs following the 8086 of 1978, the Intel 80286 of 1982, and 1985's i386.
A microprocessor is a computer processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, and control circuitry required to perform the functions of a computer's central processing unit (CPU). The IC is capable of interpreting and executing program instructions and performing arithmetic operations. The microprocessor is a multipurpose, clock-driven, register-based, digital integrated circuit that accepts binary data as input, processes it according to instructions stored in its memory, and provides results as output. Microprocessors contain both combinational logic and sequential digital logic, and operate on numbers and symbols represented in the binary number system.
The Pentium is a x86 microprocessor introduced by Intel on March 22, 1993. It is the first CPU using the Pentium brand. Considered the fifth generation in the 8086 compatible line of processors, its implementation and microarchitecture was internally called P5.
x86 is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel based on the 8086 microprocessor and its 8-bit-external-bus variant, the 8088. The 8086 was introduced in 1978 as a fully 16-bit extension of 8-bit Intel's 8080 microprocessor, with memory segmentation as a solution for addressing more memory than can be covered by a plain 16-bit address. The term "x86" came into being because the names of several successors to Intel's 8086 processor end in "86", including the 80186, 80286, 80386 and 80486. Colloquially, their names were "186", "286", "386" and "486".
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.
The Cyrix 5x86 is a line of x86 microprocessors designed by Cyrix and released on June 5 of 1995. Cyrix, being a fabless company, had the chips manufactured by IBM. The line came out about 5 months before the more famous Cyrix 6x86. The Cyrix 5x86 was one of the fastest CPUs ever produced for Socket 3 computer systems. 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.
The Am5x86 processor is an x86-compatible CPU announced in November of 1995 by AMD for use in 486-class computer systems. It began shipping in December of 1995, with a base price of $93 per unit in bulk quantities. Before being released, it was in development under the codename "X5".
The Am386 CPU is a 100%-compatible clone of the Intel 80386 design released by AMD in March 1991. It sold millions of units, positioning AMD as a legitimate competitor to Intel, rather than being merely a second source for x86 CPUs.
NexGen, Inc. was a private semiconductor company based in Milpitas, California, that designed x86 microprocessors until it was purchased by AMD in 1996. NexGen was a fabless design house that designed its chips but relied on other companies for production. NexGen's chips were produced by IBM's Microelectronics division in Burlington, Vermont alongside PowerPC and DRAM parts.
The NEC V20 is a microprocessor that was designed and produced by NEC. It is both pin compatible and object-code compatible with the Intel 8088, with an instruction set architecture (ISA) similar to that of the Intel 80188 with some extensions. The V20 was introduced in March 1984.
The x86 instruction set refers to the set of instructions that x86-compatible microprocessors support. The instructions are usually part of an executable program, often stored as a computer file and executed on the processor.
Socket 3 was a series of CPU sockets for various x86 microprocessors. It was sometimes found alongside a secondary socket designed for a math coprocessor chip, such as the 487. Socket 3 resulted from Intel's creation of lower voltage microprocessors. An upgrade to Socket 2, it rearranged the pin layout. Socket 3 is compatible with 168-pin socket CPUs.
The Rise mP6 was a superpipelined and superscalar microprocessor designed by Rise Technology to compete with the Intel Pentium line.
x87 is a floating-point-related subset of the x86 architecture instruction set. It originated as an extension of the 8086 instruction set in the form of optional floating-point coprocessors that work in tandem with corresponding x86 CPUs. These microchips have names ending in "87". This is also known as the NPX. Like other extensions to the basic instruction set, x87 instructions are not strictly needed to construct working programs, but provide hardware and microcode implementations of common numerical tasks, allowing these tasks to be performed much faster than corresponding machine code routines can. The x87 instruction set includes instructions for basic floating-point operations such as addition, subtraction and comparison, but also for more complex numerical operations, such as the computation of the tangent function and its inverse, for example.