AMD K6-III
The K6-III, code-named "Sharptooth", was an x86 microprocessor manufactured by AMD, released on 22 February 1999, with 400 and 450 MHz models. It was the last Socket 7 desktop processor. For an extremely short time after its release, the fastest available desktop processor from Intel was the Pentium II 450 MHz. However, the K6-III also competed against the Pentium III "Katmai" line, released just days later on February 26. "Katmai" CPUs reached speeds of 500 MHz, slightly faster than the K6-III 450 MHz. K6-III performance was significantly improved over the K6-2 due to the addition of an on-die L2 cache running at full clock speed. When equipped with a 1MB L3 cache (on the motherboard) the 400 and 450 MHz K6-IIIs is claimed by Ars Technica to often outperform the hugely higher-priced Pentium III "Katmai" 450- and 500-MHz models, respectively.
Architecture
In conception, the design is simple: it was a K6-2 with on-die L2 cache. In execution, however, the design was not simple; with 21.4 million transistors. The pipeline was short compared to that of the Pentium III and thus the design did not scale well past 500 MHz. Nevertheless, the K6-III 400 sold well, and the AMD K6-III 450 was clearly the fastest x86 chip on the market on introduction, comfortably outperforming AMD K6-2s and Intel Pentium IIs.
AMD K6-2
The K6-2 was an x86 microprocessor introduced by AMD on May 28, 1998, and available in speeds ranging from 266 to 550 MHz. An enhancement of the original K6, the K6-2 introduced AMD's 3DNow! SIMD instruction set, featured a larger 64 KiB Level 1 cache (32 KiB instruction and 32 KiB data), and an upgraded system-bus interface called Super Socket 7, which was backward compatible with older Socket 7 motherboards. It was manufactured using a 0.25 micrometre process, ran at 2.2 volts, and had 9.3 million transistors.
History
The K6-2 was designed as a competitor to Intel's flagship processor, the significantly more expensive Pentium II. Performance of the two chips was similar: the previous K6-2 tended to be faster for general-purpose computing, while the Intel part was faster in x87 floating-point applications. To battle the Pentium 2's dominance on floating point calculations the K6-2 was the first CPU to introduce a floating point SIMD instruction set (dubbed 3DNow! by AMD), which significantly boosted performance. However programs needed to be specifically tailored for the new instructions and despite beating Intel's SSE instruction set to market, 3DNow achieved only limited popularity.
