Actually difficult to know if it was Keller. Apple bought PA Semi which is where he came from. But he came on as a VP after it was founded by other engineers who had worked on the Alpha chips a year before that. Did he make the difference? Who knows.

What does seem to be constant is that the best CPU designs have been touched by the hands of people who can trace their roots to North Eastern US. Maybe the correlation doesn't exist and the industry is small and incestuous enough that most designs are worked on by people from everywhere, but sometimes it seems like some group at DEC or Multiflow stumbled on the holy grail of CPU design and all took a drink from the cup.