This depends on manufacturer's implementation and I don't know how it's implemented on this mainboard in detail (vendors don't give out such information usually).
The ADT sensor might be sampling the same IOH temperature and the IOH sensor does. The Intel IOH value comes straight from the chip itself (internal diode), however maybe the sensor is differently calibrated, or there's a time difference between the samples. Or maybe the ADT sensor value measures value of the chip's surface.
I'll leave the Intel IOH value, since this is a legitimate reading from the primary source.
Isn't the "CPU Core Temperature" just the highest reading of all cores? PECI usually lists this as the highest value.
Can you attach a screenshot of HWiNFO64 and the Intel tool side by side ? Also please attach the respective DBG file.