Intel locates their core temperature sensors on the hottest spots on the core which is completely different than what AMD does. Core temperatures can and do vary instantaneously.
The other thing to keep in mind is that Intel only designed and calibrated these sensors to control thermal throttling at around 100C and thermal shut down at approximately 125C to 130C. They were never intended to be used for 100% accurate core temperature reporting, especially when the CPU is lightly loaded and a long ways away from the calibration temperature.
If you equally load the cores with something like Prime 95 Small FFTs then you will typically see a variation of +/- 5C. The variation will be greater when you are running any app that is not equally loading the cores.
As long as your CPU is not reaching the thermal throttling temperature then there is no need to worry too much about the core temperature. If the Thermal Status area of RealTemp shows that your CPU is OK then that means it has not reached the thermal throttling temperature since you booted up so no worries.
RealTemp T|I Edition