I take back "often" and "seldom" because after having heavily loaded the
laptop with computations, I observed around 400 MHz for all 8 cores
twice. Though I did observe what I wrote, I cannot claim "often" and
"seldom" for the future behavior beyond reasonable doubt.
So instead of
“… often (but not always!) the same: a few cores often (but not always!)
resist and run at higher frequencies up to 2.4 GHz. Only seldom …“
please read
“… sometimes similar: a few cores sometimes resist and run at higher
frequencies up to 2.4 GHz. Sometimes …”