The benchmarks for all these CPUs that my personal view point is based on are all out there. Anandtech was my favorite source for this at the time due to relatively detailed testing and a clear understanding of the implications of architecture decisions. The complete history of their contemporaneous reviews are still online and userbenchmark.com has independent data on these older CPUs as well although obviously with less control over potential mitigating factors.
AMD was struggling to release CPUs that were competitive against year old Intel Core 2 Duos which remained the status quo through their Bulldozer architecture. Things started turning around with Ryzen when a combination of architecture improvements and typical workloads taking more advantage of multicore flipped the script.
The bits about "true" multicore are also sketchy considering Bulldozer was using shared L2, fetch/decode, and floating point hardware on each module and calling a module two "cores" for marketing purposes.
K7/K8 were great, and while the follow-on K10 Athlon2/Phenom/etc were definitely not bad, they weren't great and they were competing against Conroe/Core2 onwards. That kind of tag-team trading places highlights how (mostly) good the CPU market is now, both AMD and intel are putting out some really nice products with variety so you can pick the most suitable for you, but there's no default "just pick [company]"
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.
AMD was struggling to release CPUs that were competitive against year old Intel Core 2 Duos which remained the status quo through their Bulldozer architecture. Things started turning around with Ryzen when a combination of architecture improvements and typical workloads taking more advantage of multicore flipped the script.
The bits about "true" multicore are also sketchy considering Bulldozer was using shared L2, fetch/decode, and floating point hardware on each module and calling a module two "cores" for marketing purposes.
https://www.anandtech.com/show/4955/the-bulldozer-review-amd...