That's good to know. I wasn't really intending to get in to an argument about whether rustc threads well, because although I've used Rust a fair bit I haven't

That's good to know. I wasn't really intending to get in to an argument about whether rustc threads well, because although I've used Rust a fair bit I haven't built any large projects in it. If people have and it uses all their cores, I totally believe them. What I was trying to do is point out that the correct response to "Rust doesn't thread well" is not "but have you run it on a workstation?". Laptop chips for the first time are extremely competitive for single threaded workloads, because the individual cores in large chips now have equivalent power budgets, you just get a bunch more of them. "Actually, it does thread well" is totally fine as a response, and I'm not going to claim otherwise.