The poor K6-III... The timing of the Athlon launch stole its thunder. Otherwise I think it would have been looked at as much more significant in CPU history. It really did level the playing field against Intel.
I remember the difference between a K6-2 500 system I had and a similar Duron 600 system I built for someone felt like a lot more than 132Mhz and some cache. Maybe it was a driver issue. I'd love to have either system back, now.