[Delk]

AMD did become at least competitive in high end CPUs with the original Athlon or Athlon XP. Not sure whether they were faster than the Pentium 3 but they weren't trailing.

So perhaps a bit more than a couple of years, but my impression is also that they fell behind on (single-thread) performance for a long time after that.

I've also understood that in more ancient history AMD CPUs sometimes beat contemporary Intel parts in performance, although releasing their parts later than Intel. I'm not sure that's relevant to any remotely recent developments anymore though.