Soft cores in FPGAs typically run at 100 MHz or less -- often 25 or 50 MHz for sophisticated OoO designs. SiFive's December 2016 "HiFive1" had a 320 MHz 32 bit

Soft cores in FPGAs typically run at 100 MHz or less -- often 25 or 50 MHz for sophisticated OoO designs. SiFive's December 2016 "HiFive1" had a 320 MHz 32 bit SoC with one in-order 32 bit core. SiFive's early 2018 "HiFive Unleashed" had an SoC with five in-order 1.0 - 1.5 GHz (mine has worked stable at 1.45 GHz for 3+ years) cores. This "HiFive Unmatched" has an SoC with five dual issue in-order 1.0 to 1.5 GHz cores (mine works fine at 1.5). We're talking about 30 times faster MHz than an FPGA soft core would be. SiFive have never not had "proper" SoCs. Their business is selling IP for people to use to make SoCs. They provide early access to cores running on FPGAs at a small fraction of SoC speed to customers for evaluation purposes.