This actually depends on silicon quality. The mainboard manufacturers generally configure the OOB CPU voltages higher than they need to be in anticipation of ha

This actually depends on silicon quality. The mainboard manufacturers generally configure the OOB CPU voltages higher than they need to be in anticipation of handling crappy silicon. If you have a higher binned CPU then you can reduce that voltage and still be stable at a given clock, the chip will then be able to boost higher because there will be more thermal headroom.