If AMD makes a comeback, how did they do it? Not enough competition and Intel got complacent or what? Or did they just reach the limits and it's not possible anymore to keep the lead and prevent AMD from catching up?
386DX - copied Intel design verbatim (1:1 microcode). Got sued, won only because Intel had multiple source agreements with IBM.
K6 - purchased NexGen. Designed 100% by outsiders.
K7 - once again hired somebody else's engineers. This time almost whole DEC Alpha design team.
K8 - DEC people had some more steam left in them.
K9-Zen period - no more companies to take over and claim credit for their designs, add terrible management bleeding engineering talent while burning money on stupid ideas like Seamicro = in house garbage with 50% Intel IPC.
Zen - finally managed to rehire competent ex DEC engineer Jim Keller after his successful career at Apple.