Different chips have different limits. I used to do some of this competitively back in the day. Different architectures can't get as high max frequencies, some

Different chips have different limits. I used to do some of this competitively back in the day. Different architectures can't get as high max frequencies, some respond differently under the extreme cold. These records are typically done using liquid nitrogen or phase change cooling and a lot of chips will freeze up below a certain temperature. Then its also a toss up between different individual cpus of the same model. It's a bit of a crapshoot.