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> China was investing heavily in RISC-V, which implies that either they're going to have to settle for permanently crippled perf Not quite. RISC-V application

> China was investing heavily in RISC-V, which implies that either they're going to have to settle for permanently crippled perf Not quite. RISC-V application class processors are a new development. They are starting from behind but they are improving faster than the competition. The SpacemiT K3 is 4 times faster than the K1 for example. The Alibaba C950 will be about Apple M1 level performance. And even faster designs are already in the works. RISC-V is not “permenantly crippled”. It will catch up and maybe surpass ARM. It is more an economy of scale issue than anything.

hylaride 1mo ago
My understanding is that RISC-V needs both economies of scale AND chips that are manufactured at the bleeding edge fabs (smallest dies, etc) which is a lot more expensive. It's a chicken and egg problem as there's not (yet?) demand. The architectural limitations will remain until there's incentive to work on it. In many ways it's not much different than Linux was in the 1990s. It was cheap and useful, but often not as performant as commercial OSes (UNIX or even windows) until big corporate money came in and started piling resources into it. Distribution fragmentation was also an issue, which could still cause headaches for RISC-V (especially if some companies start adding proprietary performance extensions that others can't). So I think it remains to be seen how RISC-V will pan out (eg will the cloud vendors see enough of an ROI supporting it for higher end computing than buying ARM licences).
- RetroTechie 1mo ago
  > RISC-V needs both economies of scale AND chips that are manufactured at the bleeding edge fabs (smallest dies, etc) which is a lot more expensive. It's a chicken and egg problem as there's not (yet?) demand Whatever leading-edge fab capacity (mostly TSMC) was available, is now tied up to supply the ongoing AI boom. And will remain so for the foreseeable future. Even if you'd have a RISC-V product for which demand/economics work out, chances are those fabs' order books are filled. Also: design is done in many places, but actual fabrication of RISC-V SoCs in largely centered in China. Which (afaik) doesn't lack IC fabrication capacity. But does lag in leading-edge fab capacity. So: off to older nodes. Which may hurt perf/W, cost effectiveness or transistor budget. Or pay a premium (pricing products out of markets), limited production, or long lead times. Of course this affects ARM based & other products too. But they've been in the optimization / mass fabrication / distribution pipeline much longer than most RISC-V based products. Catching up takes time, and top-tier fab capacity being swiped by Nvidia & co doesn't help to shorten that process. I don't think it's a demand problem. Consumers don't care what powers their phone/tablet/laptop as long as it does its job. So in principle the market is there (yeah.. I understand issues like Google still working on Android-RISC-V, Windows users probably wanting x86 for legacy software etc).
  - hylaride 1mo ago
    It can be a demand problem. People/companies aren't going to spend the time optimizing (including compilers/code) if there's no payoff that's greater than the delta for an arm chip. That being said, demand from and via China (which has a geopolitical case for wanting to see risc-v succeed) will probably end up being what drives it forward.
  - LeFantome 1mo ago
    The SiFive, Tenstorrent, Rivos (Meta), and Qualcomm RISC-V chips are not fabricated in China. I mean, Chinese suppliers may license their cores of course. But even Chinese RISC-V makers were going to use TSMC until US sanctions got in the way.

hylaride 1mo ago

My understanding is that RISC-V needs both economies of scale AND chips that are manufactured at the bleeding edge fabs (smallest dies, etc) which is a lot more expensive. It's a chicken and egg problem as there's not (yet?) demand. The architectural limitations will remain until there's incentive to work on it. In many ways it's not much different than Linux was in the 1990s. It was cheap and useful, but often not as performant as commercial OSes (UNIX or even windows) until big corporate money came in and started piling resources into it. Distribution fragmentation was also an issue, which could still cause headaches for RISC-V (especially if some companies start adding proprietary performance extensions that others can't). So I think it remains to be seen how RISC-V will pan out (eg will the cloud vendors see enough of an ROI supporting it for higher end computing than buying ARM licences).

RetroTechie 1mo ago
> RISC-V needs both economies of scale AND chips that are manufactured at the bleeding edge fabs (smallest dies, etc) which is a lot more expensive. It's a chicken and egg problem as there's not (yet?) demand Whatever leading-edge fab capacity (mostly TSMC) was available, is now tied up to supply the ongoing AI boom. And will remain so for the foreseeable future. Even if you'd have a RISC-V product for which demand/economics work out, chances are those fabs' order books are filled. Also: design is done in many places, but actual fabrication of RISC-V SoCs in largely centered in China. Which (afaik) doesn't lack IC fabrication capacity. But does lag in leading-edge fab capacity. So: off to older nodes. Which may hurt perf/W, cost effectiveness or transistor budget. Or pay a premium (pricing products out of markets), limited production, or long lead times. Of course this affects ARM based & other products too. But they've been in the optimization / mass fabrication / distribution pipeline much longer than most RISC-V based products. Catching up takes time, and top-tier fab capacity being swiped by Nvidia & co doesn't help to shorten that process. I don't think it's a demand problem. Consumers don't care what powers their phone/tablet/laptop as long as it does its job. So in principle the market is there (yeah.. I understand issues like Google still working on Android-RISC-V, Windows users probably wanting x86 for legacy software etc).
- hylaride 1mo ago
  It can be a demand problem. People/companies aren't going to spend the time optimizing (including compilers/code) if there's no payoff that's greater than the delta for an arm chip. That being said, demand from and via China (which has a geopolitical case for wanting to see risc-v succeed) will probably end up being what drives it forward.
- LeFantome 1mo ago
  The SiFive, Tenstorrent, Rivos (Meta), and Qualcomm RISC-V chips are not fabricated in China. I mean, Chinese suppliers may license their cores of course. But even Chinese RISC-V makers were going to use TSMC until US sanctions got in the way.