Editing AMD K6 (section)

==Background==
[[Image:Amdk6 arch.svg|left|thumb|The AMD K6 architecture]]

The AMD K6 is a [[superscalar processor|superscalar]] [[P5 (microarchitecture)|P5]] [[Pentium]]-class [[microprocessor]], manufactured by [[AMD]], which superseded the [[AMD K5|K5]].

The AMD K6 is based on the Nx686 microprocessor that [[NexGen]] was designing when it was acquired by AMD. Despite the name implying a design evolving from the [[AMD K5|K5]], it is in fact a totally different design that was created by the NexGen team, including chief processor architect Greg Favor,<ref>p. 48, [https://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=755466 "AMD 3DNow! technology: architecture and implementations"], S. Oberman, G. Favor, and F. Weber, ''IEEE Micro'' '''19''', #2 (March/April 1999), pp. 37–48, {{doi|10.1109/40.755466}}.</ref><ref>[http://www.cs.clemson.edu/~mark/architects.html Who are the Computer Architects?], Mark Smotherman, Clemson University, updated June 9, 2010.</ref> and adapted after the AMD purchase. The K6 processor included a feedback dynamic instruction reordering mechanism, [[MMX (instruction set)|MMX]] instructions, and a floating-point unit (FPU). It was also made [[Pin-compatibility|pin-compatible]] with Intel's Pentium, enabling it to be used in the widely available "[[Socket 7]]"-based motherboards. Like the [[AMD K5]], Nx586, and Nx686 before it, the K6 translated x86 instructions on the fly into dynamic buffered sequences of [[micro-operation]]s. A later variation of the K6 CPU, [[AMD K6-2|K6-2]], added [[floating-point]]-based SIMD instructions, called [[3DNow!]].

The K6 was originally launched in April 1997, running at speeds of 166 and 200&nbsp;MHz. It was followed by a 233&nbsp;MHz version later in 1997. Initially, the AMD K6 processors used a Pentium II-based [[performance rating]] (PR2) to designate their speed.<ref>{{cite web |last1=Shimpi |first1=Anand Lal |title=AMD K6 Review |url=https://www.anandtech.com/show/42/amd-k6-review |website=[[AnandTech]] |access-date=14 September 2022 |date=3 April 1997}}</ref> The PR2 rating was dropped because the rated frequency of the processor was the same as the real frequency. The release of the 266&nbsp;MHz version of this chip was not until the second quarter of 1998, when AMD was able to move to the 0.25-micrometre manufacturing process. The lower voltage and higher multiplier of the K6-266 meant that it was not fully compatible with some Socket 7 motherboards, similar to the later [[AMD K6-2|K6-2]] processors. The final iteration of the K6 design was released in May 1998, running at 300&nbsp;MHz.
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File:AMD K6 (Model6) 200ALYD ZS-PMax - Stack-DSC05068-DSC05133 (22382082681).jpg|A delidded AMD K6 processor
File:AMD@350nm@K6@Model6 - (cpuid562)@AMD-K6-233APR@3.3V CORE C9743EJFW 1997 AMD DSCx8 polysilicon@macrolens.jpg|Die shot of an AMD K6-233APR processor
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