i dont get the core speed deal

[PFC Cavazos]

i overclocked my CPU 3770k to 4.2 and it is stable. but when i open CPU-Z on the core speed it says x16.0 (16-42) then it says x42.0 (16-42) i dont quite understand why.

 

[Soulage]

It's 16-42 x the base clock, so 42 x 100 = 4200 or 4.2GHz, at 16 it would have clocked down to an idle / light use speed of 1.6GHz.