If it is stable, do not worry.
Is this stock speed? Try seeing if you need to press a key combo by searching online to unlock advanced options. CPU chips don't come with a set voltage, but a range. The stock voltage each individual chip runs at is the VID, for example the VID of a Q9450 was around 1.15-1.25Vcore. Unless it is causing instability I would not worry, and check cpu-z in the OS for the Vcore, as the Vcore from BIOS to OS usually drops (Vdrop) and under load drops further (Vdroop).
If idle, the voltage could be about 1V depending on how much it is throttled, saving power. I am not sure they add 10% or not, but I would think it will only be added once the bus speed is changed.