If you actually measure voltages (I have), you'll find out that that is not always true... in some cases, yes, in most cases, no. Depends from MB manufacturer and model. AMD chipsets usually allow this and the declared settings are what you can actually measure on the board. Intel though... nah, way too many failsafes in place to let you do whatever you want, even though the firmware will report that you've set it a certain way (Vcore = 2V, as in your case).