There is the Berkley Out of Order Machine BOOM https://github.com/ucb-bar/riscv-boom, its performance approaches those of modern intel processors in core mark, I think it would probably be possible to eventually match them.
Thanks for the plug, but just to clarify, while BOOM approaches the cycles/instruction of Intel's server cores, it does not approach their clock frequencies! Still, I'd say its competitive with the current mobile processor segment. =)
