Ik there is an 'ez mode' for OC in the bios but I have had 0 experience In overclocking
Never ever use this it always puts more voltage than is needed.
The Pro 4 boards are your basic cheap boards with poor power delivery.
Their really no answer to your question because all processors will react a bit different and not all will overclock the same.
With that board I would try to keep the Vcore voltage at 1.3 or lower for long term use how far you can overclock on that voltage depends on how good of a chip you got.