Partially, but the shift is more in the amount of power required to constantly serve interrupts. That’s essentially what these flags enable. Where previously the kernel would be more lax about scheduling such things, this let’s all those interrupts off the chain. More interrupts = more power draw. The ARM and AMD extensions mean to reduce that in a meaningful way, though.

In modern processors, using performance can save power. By only powering up one core for a little while, even though it’s at a higher clock speed, some CPUs save energy by going back to sleep as soon as possible.

In my own experiments, powersave often did the opposite, keeping six or seven cores moderately active with light usage (because of the low clock speeds) and using more power than when I used performance.

Real life will vary by CPU and motherboard, of course.