Why all of my CPUs scale to the max freqency when only one of them is runing at 100% and all the others at around 0%?

I am running Ubuntu 18 on a System76 Oryx Pro 4 with an i7 8th gen 6 cores.

As you can see from the following image, when all CPUs usage is <= 6%, all CPUs run at a frequency of 800MHz. enter image description here

However, as soon as I run an infinite while loop in a terminal which causes only CPU5 usage to increase to 100%, all CPUs (even those with 0% usage) scale to 4,100 MHz which is the maximum CPU freq. enter image description here

Is this the expected behavior? Also, is there any way that the behavior can be changed so that only the frequency of the CPU with 100% usage increases to the top speed.

Any CPUs using value prediction, dynamic instruction reuse?

There is a lot of research about techniques that try to reuse the previous result of an instruction, either memory loads or arithmetic, such as dynamic instruction reuse, value prediction, based on the concept of value locality.

What I wonder if there is any commercial CPU from Intel/AMD/ARM that actually uses any of these techniques, or are they still far away from being implemented in CPUs?

I mostly see these techniques as the runtime, CPU version of compiler optimizations such as common-subexpression elimination, loop invariant code motion, redundant load removal, catching cases that cannot be handled due to pointer aliasing, side-effects, etc.