Actually no the PS4 CPU speed has never been disclosed by SCE or any other developer and it's protected under NDA.
Lots of people like to pretend that the Xbox has something better than the PS4 but in reality CPU only benchmarks show ps4 having superior performance.
Nothing publicly is known about the PS4 CPU clock speed.
While I don't know if the speed of PS4's CPU has ever been released or not, the truth is that we know that the CPU inside the Xbox One is faster thanks to Ubisoft.
Ubi did a GDC conference in 2014 and they revealed some benchmarks that showed that X1's CPU had some advantage over the PS4:
Sure, it's not by much, but it is more powerful.
Please excuse my bad English.
Currently gaming on a PC with an i5-4670k@stock (for now), 16Gb RAM 1600 MHz and a GTX 1070
Steam / Live / NNID : jonxiquet Add me if you want, but I'm a single player gamer.