Comment by IshKebab

Yeah Rivos apparently taped out a high performance server class core (probably only a test chip I'd guess) before Meta bought them.

There are plenty of multi core designs (that's easy) but they aren't very fast.

In terms of open source XiangShan is the most advanced as far as I know. It's fairly high performance out-of-order.

I don't think there's anything M5-level and probably won't be for a while (it took ARM decades so it's not a failing). I doubt we'll see any serious RISC-V laptops because there probably isn't demand (maybe Chromebooks though?). More likely to see phones and servers because Android is supporting RISC-V, and servers run Linux.

In terms of extensions I think it's pretty much all there. Probably it needs some kind of extension to make x86 emulation fast, like Apple did. The biggest extension I know of that isn't ratified is the P packed SIMD one but I don't know if there's much demand for that outside of DSPs.