My 3950x single core boost is not going any where near max 4.7ghz. I have updated to the latest 18.104.22.168 bios and enabled PBO in the bios. Temps are consistently around 60c during idle. Cinebench scores for single core is less than 500 and so is the case with cpuz as well.
System specs :
Asrock x370 taichi
32gb 3333mhz corsair.
Ironically my overclocked 1700 shows better single thread score on the same mobo & ram.