AMD revealed that it is working on not one, but two brand-new, built-from-scratch CPU architectures. It has licensed the ARMv8 ISA and, in Dr. Su's words, "we are already well on our way to developing custom ARM cores." At the same time, AMD is building a brand-new, x86-compatible CPU core that will serve to replace Bulldozer and its lineage.

I'm not quite sure whether the biggest news here is the announcement of a new high-end x86 architecture from AMD or the fact that ARMv8 is getting the same treatment.

Since we're talking about a replacement for Bulldozer, this is an entirely different class of beast from the "Puma+" and Cortex-A57 cores in the first SkyBridge parts. AMD's execs noted that these are high-frequency, high-performance CPU cores that will span the range from laptops to desktops to servers—and not just "microservers." We don't know exactly how big they'll be compared to Bulldozer or, say, Haswell. The smartest play might be to aim for something a little smaller than those cores, but that's the basic class of performance they're undoubtedly meant to achieve.

AMD is returning to its roots, aiming to produce a best-in-class big core.