I hope you were able to change your voltage levels with my suggestion. Let us know what happens.

One point I was not clear about is that it is not ASRock and their Auto BIOS settings that cause the higher voltage, it is the CPU itself when used with Adaptive voltage. All Z87 boards made by anyone will do that. The Auto setting is really Adaptive with an automatic positive (+) offset that is really not limited, as long as the Offset voltage is also set to Auto.

Earlier generation Intel CPUs work in a similar way. The CPU will "request" a certain voltage level from the board with what is called a VID. VIDs are usually higher than necessary. The high VIDs may be there to compensate for a board's CPU power source that is to weak to supply the voltage, but still allow the CPU to get enough power. Since better boards are able to provide all the voltage the VID requests, we get most or all of it, which is usually to much.

Mother boards and the BIOS settings they provide that are designed to OC give us much more control over the CPU voltage. But that means that we must configure those settings correctly, and have the information and knowledge needed to do that appropriately.