The HiFive Unmatched will certainly be the best performing freely available RISC-V PC for the moment. Alibaba's XT910 might be similar but so far they're only using it internally.
The U74 cores in the Unmatched are very similar uarch to the ARM A55 (as found in boards such as the Odroid C4) minus NEON. That's a good step better than the A53 found in the Raspberry Pi 3, but not as good as the out-of-order A72 in the Pi 4. Overall performance on many tasks may be similar to or even better than the Pi 4 as while the CPU cores are slightly worse the RAM and I/O are better, with the Unmatched having 16 GB DDR4, an M.2 slot for SSD, and PCIe for a real graphics card (SiFive demonstrates it with a Radeon RX 580).
Obviously it's not price-competitive with a Pi at this point, as it's still low volume.
The best RISC-V cores are around 5 or 6 years behind ARM in performance, but catching up. SiFive claims A72 equivalence for the U84 out of order core they announced 14 months ago (which will probably start to be available in silicon around the end of 2021) and AliBaba claims A73 equivalence for the XT910.
Obviously no one has an Apple M1 equivalent RISC-V core at this point, but neither do ARM's customers.
The U74 cores in the Unmatched are very similar uarch to the ARM A55 (as found in boards such as the Odroid C4) minus NEON. That's a good step better than the A53 found in the Raspberry Pi 3, but not as good as the out-of-order A72 in the Pi 4. Overall performance on many tasks may be similar to or even better than the Pi 4 as while the CPU cores are slightly worse the RAM and I/O are better, with the Unmatched having 16 GB DDR4, an M.2 slot for SSD, and PCIe for a real graphics card (SiFive demonstrates it with a Radeon RX 580).
Obviously it's not price-competitive with a Pi at this point, as it's still low volume.
The best RISC-V cores are around 5 or 6 years behind ARM in performance, but catching up. SiFive claims A72 equivalence for the U84 out of order core they announced 14 months ago (which will probably start to be available in silicon around the end of 2021) and AliBaba claims A73 equivalence for the XT910.
Obviously no one has an Apple M1 equivalent RISC-V core at this point, but neither do ARM's customers.