[adgjlsfhk1]

why does it take so long? I totally understand for leading edge products on new nodes why it would, but for chips on mature processes, what's the bottleneck between design and sale? I know the round trip time from the foundries is ~3 months. Is the rest validation? It feels like it would be really valuable to be able to reduce the time to ~1 year (even if that came at the cost of power, area or a moderate amount of performance). Shortening the feedback loop here would be super helpful for designers and programmers to be able to experiment with new paradigms faster I would think.

[brucehoult]

Largely because in the Arm and RISC-V worlds company A designs the CPU core, then at some point company B decides to license the core to make an SoC and starts designing it. Then company C manufactures the chip. Then when the chip is available companies D, E, F design boards for the chip to go on.

Traditionally in x86 Intel and AMD do all the first three steps in one company, with the stages overlapped, and feedback.

Also, Intel and AMD (and even more so Apple) don't announce a new chip until it is very close to shipping. They might have been working on it internally for five years before that.

Arm and RISC-V companies have to make public announcements when a core is nearing design completion, to give a chance for companies such as Allwinner and Rockchip and Broadcom and Mediatek and Sophgo and Starfive to take a look at the specs and decide that it might be interesting to build a chip using that core.

> I know the round trip time from the foundries is ~3 months.

That's only if the chip works first time. Many don't and need several re-spins. I believe 3 or 4 is not uncommon. And variable amounts of re-design and re-layout and re-verify time between each of those ~3 months at the foundry.

Given that, it would be a brave company that went straight to mass-production without a round of test chips first, so you've got 2x ~3 months, plus "bring up" time in between, even in the best case.