Lowering voltage on Snapdragon 8 Elite cores

The article mentions that by ditching the efficiency cores and lowering the voltage on their new "performance" cores they have achieved the same efficiency. My bachelor is on electronics eng, and my professional career has nothing to do with it. I know there's more to it that that said in the article: Why they've never tried to lower voltage before instead of having efficiency cores? And what do they mean, they lowered voltage, are we talking 5V range to 3V range?