It depends on what you call "high performance".

I have in my hands one of the new SpacemiT K3 machines. It arrived today. I'm comparing it to several other things, and finding that it is pretty comparable to a "late 2012" Mac Mini with a i7-3720QM with base 2.6 GHz turbo 3.6 GHz running Ubuntu 24.04. They are quite close in feel for general use, web browsing, code editing, watching YouTube etc. The Mac is a little faster on many things, a LOT slower on others (anything that can use 8 cores, obviously).

You might say that's not "high performance" but we thought it was pretty good a dozen years ago.

The previous SpacemiT K1 chip two years ago was more like one of the last Pentium IIIs or PowerpC G4s, except with a lot more cores.

SpacemiT have a next generation K5 coming out, they say, at the end of the year. Tenstorrent have their new Ascalon-X core comparable to Apple's late 2020 M1 — and designed by the same guy who designed the M1. They've taped out a chip using that and say they'll be selling a dev board in Q2 or Q3. For now the first version is using an old chip process and it will be running at half the clock speed of the M1, but that's still going to be a very decent machine.

The HiFive Unleashed was of course 8 years ago. Since then there have been the HiFive Unmatched (roughly like Cortex A55) and the HiFive Premier P550 (a bit better than Cortex A72, other than no SIMD).