AMD Ex-Chip Architect, Jim Keller Says He’s Worked On Zen 1, Zen 2, Zen 3 But K12 ARM CPU Has Been Canceled By His Former Employer
The ‘Future of Compute’ conference was held by the Department of Computer Science and Automation, Indian Institute of Science, where Jim Keller gave a brief overview of the various projects he has worked on and the fundamentals of chip design.
Jim says that when he was at AMD, he worked on Zen 1 and laid out the plans for Zen 2 and Zen 3, meaning Zen 3 could probably be the last Jim Keller design we got from him if the latest Zen 4 and Zen 5 projects could be designed in-house by a new team at AMD. During his time at AMD, Jim and his team noticed that the cache design for ARM and x86 CPU was largely the same as the execution unit and the only difference between the two processor architectures was the decoder unit, so they decided to work on a new chip, known to us as K12 which was later canceled by AMD.
Jim Keller reveals that the K12 ARM CPU project was canceled by certain executives after he left the company. As he puts it, most executives are afraid to change things, but being an architect himself he is not afraid of changes like this and the work he did during his time at AMD was ‘Fun’.
As for AMD’s K12, the ARMv8-A based CPU was designed to be launched together with the Zen project and was expected to focus on high-frequency and power-efficient environments, targeting the dense server, embedded and semi-custom market segments. AMD has since released several semi-custom server chips based on the Zen core architecture, and they are moving into the dense computing segment next year with their new Zen 4C architecture, which debuts on the EPYC Bergamo Platform† AMD’s embedded chips also use Zen silicon, so it seems AMD had a very different plan to use Zen for its entire computing needs rather than relying on a separate ARM-focused architecture.
“But I’ll tell you from my point of view, if you look at computing solutions, whether it’s x86 or ARM or even other areas, that’s an area where we focus on investment,” AMD CFO Devinder Kumar responded to a question about the the company’s vision for competitive Arm chips. “We know compute very well. Even ARM, as you pointed out, we have a very good relationship with ARM. And we understand that with that particular product, our customers want to collaborate to deliver the solutions. We are ready to continue and do so even if it’s not x86, although we believe x86 is a dominant force in that area.”
That said, AMD’s CFO, Devinder Kumar, has already stated that they are ready to make ARM chips if there is a demand for them. AMD is also entering the semi-custom arena where it plans to use third-party chiplets in the near future, so that’s also something that ARM chips can use, but that won’t be a full internal design AMD made with K12. when Jim was around. Jim also came back to Intel 2018 and let in 2020 having worked on several chip projects and is currently the Acting CTO at Tenstorrent.