What exact does undervolting do?

[JohnyW]

Hi there. I know, that undervolting decreases voltage of CPU/GPU. But I want to know, how exactly does it do....

IMHO it works like this:
I have a CPU with default voltage set to 1.2V, but it uses max 1.1V. under load.
So it means 1.2V is led into my CPU. Inside those 1.2V is 0.1V that my CPU will not use and it has to do something (according to physical laws)..so it turns into an extra heat?

So if I undervolt by -0.1V then will be led into my cpu 1.1V?? -the same value that can CPU under load use?

Am I right?? If not, please, can you explain it to me?? I am really interested in.

[FULLMETALJACKET]

That's not quite how it works.
When you undervolt the CPU you're changing the voltage offset in which the chip will work. By setting it at -100mv, you're forcing it to work with 100mv less than it normally would. Voltage changes according to load and frequency, so you're basically changing the voltage all across the board.

Less voltage = less current going through the chip = less heat output = better efficiency (higher boost clocks and/or cooler temperatures)