AMD K6The K6 microprocessor was launched by AMD in 1997. The main advantage of this particular microprocessor is that it was designed to fit into existing desktop designs for Pentium-branded CPUs. It was marketed as a product that could perform as well as its Intel Pentium II equivalent but at a significantly lower price. The K6 had a considerable impact on the PC market and presented Intel with serious competition. The AMD K6 is a superscalar P5 Pentium-class microprocessor, manufactured by AMD, which superseded the K5.
Pentium ProThe Pentium Pro is a sixth-generation x86 microprocessor developed and manufactured by Intel and introduced on November 1, 1995. It introduced the P6 microarchitecture (sometimes termed i686) and was originally intended to replace the original Pentium in a full range of applications. While the Pentium and Pentium MMX had 3.1 and 4.5 million transistors, respectively, the Pentium Pro contained 5.5 million transistors.
Alpha 21264The Alpha 21264 is a Digital Equipment Corporation RISC microprocessor launched on 19 October 1998. The 21264 implemented the Alpha instruction set architecture (ISA). The Alpha 21264 is a four-issue superscalar microprocessor with out-of-order execution and speculative execution. It has a peak execution rate of six instructions per cycle and could sustain four instructions per cycle. It has a seven-stage instruction pipeline. At any given stage, the microprocessor could have up to 80 instructions in various stages of execution, surpassing any other contemporary microprocessor.
Cyrix 6x86The 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 (office software as well as games) performed almost entirely integer operations. The designers foresaw that future applications would most likely maintain this instruction focus.
Parallel computingParallel computing is a type of computation in which many calculations or processes are carried out simultaneously. Large problems can often be divided into smaller ones, which can then be solved at the same time. There are several different forms of parallel computing: bit-level, instruction-level, data, and task parallelism. Parallelism has long been employed in high-performance computing, but has gained broader interest due to the physical constraints preventing frequency scaling.
Explicitly parallel instruction computingExplicitly parallel instruction computing (EPIC) is a term coined in 1997 by the HP–Intel alliance to describe a computing paradigm that researchers had been investigating since the early 1980s. This paradigm is also called Independence architectures. It was the basis for Intel and HP development of the Intel Itanium architecture, and HP later asserted that "EPIC" was merely an old term for the Itanium architecture. EPIC permits microprocessors to execute software instructions in parallel by using the compiler, rather than complex on-die circuitry, to control parallel instruction execution.
ScoreboardingScoreboarding is a centralized method, first used in the CDC 6600 computer, for dynamically scheduling instructions so that they can execute out of order when there are no conflicts and the hardware is available. In a scoreboard, the data dependencies of every instruction are logged, tracked and strictly observed at all times. Instructions are released only when the scoreboard determines that there are no conflicts with previously issued ("in flight") instructions.
NexGenNexGen, 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 company was best known for the unique implementation of the x86 architecture in its processors.
Comparison of instruction set architecturesAn instruction set architecture (ISA) is an abstract model of a computer, also referred to as computer architecture. A realization of an ISA is called an implementation. An ISA permits multiple implementations that may vary in performance, physical size, and monetary cost (among other things); because the ISA serves as the interface between software and hardware. Software that has been written for an ISA can run on different implementations of the same ISA.
