The K6-III was a short-lived x86 microprocessor manufactured by AMD.
Intended as a competitor to early Intel Pentium III models, it was essentially an improved K6-2, with an additional level of cache memory (Level 3).
The K6-III performance was quite good when introduced, but AMD experienced manufacturing problems when it tried to produce high-frequency parts. In fact, the K6-III barely reached 550 Mhz, a speed that even late-models K6-2 were able to reach. Even if, clock-for-clock, the K6-III was a better performer, it was left behind by Intel's aggressive ramp of the Pentium III.
AMD after a few months abandoned the processor while concentrating on the much more successful Athlon.