Apple hired top Intel engineers to develop the M-series chips

Apple Acquired Palo Alto Semiconductor to start off Apple's In house Chip Development process! And Jim Keller was an Employee of P.A. Semi and read up on P.A. Semiconductor's Founder(1) as well to see the RISC designs that that P.A. Semi's Founder worked(Lead Engineer) on in his career!

(1)

"P.A. Semi"

https://en.wikipedia.org/wiki/P.A._Semi

- From Wikipedia:

"P. A. Semi (originally Palo Alto Semiconductor[1]) was an American fabless semiconductor company founded in Santa Clara, California in 2003 by Daniel W. Dobberpuhl,[2][3] who was previously the lead designer for the DEC Alpha 21064 and StrongARM processors. The company employed a 150-person engineering team which included people who had previously worked on processors like Itanium, Opteron and UltraSPARC.[4] Apple Inc acquired P.A. Semi for $278 million in April 2008.[5]

P.A. Semi developed the PWRficient PA6T-1682M CPU, which was used in the AmigaOne X1000. "

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This is where Apple got their CPU cores design Chops, and the Last of the Alpha processors was SMT capable long before Intel got a hold of the person from Academia who developed SMT to design Intel's SMT which Intel Branded/Trademarked as Hyperthreading(HT)