I feel like there was a period of time around 2000 when they had some edge, at least with gamers. Soon after that they disappeared for a while and only now i'm hearing about them again.
They lost a ton of ground right around 2006 when Core2Duo became a thing and they couldn't keep up.
I remember the K8, Almost every gamer I knew had one. Everybody was rooting for AMD at the time. They were the king. Dual core, 64bit support, almost double the IPC of Intel, lower power than Intel, and more stable. The frequencies weren't as high. My 2.6Ghz Athlon 64 3700+ demolished many Intel CPU's. And then I remember when Core2Duo became a thing like you said. Completely ruined AMD in every benchmark. I believe that Intel had switched their architecture over to what was Pentium Mobile at the time and refactored it. Prescott was optimized for frequency, but the IPC was terrible, as was the heat. We had 4GHZ CPU's back in 2004.
K6 was monumental by AMD, for the price those suckers ran circles around the Pentiums of the time and were more stable at that.
Well, they're back now. Ryzen stomps Intel's latest, from what I hear
Yep. The original Athlon and Opteron was the only decent period of time when it seemed like they had a decent edge. Really because Intel so horribly botched P4. So much so they buried the Pentium name they spent billions building up.