There are two sets of CPU temperature sensors, the On-die CPU Core temperature sensors, and the Socket CPU temperatures sensors.
On-die CPU Core sensors are great for at load temperatures, because they are corrected to display the most accurate temperatures at that temperature level. Socket CPU sensors are great for idle temperatures, but are inaccurate at load (usually be 10-15C) since they are away from the CPU itself.
So reading CPU temperatures is kind of a art, and it can be a small adventure figuring out which is the proper set to be looking at. (Some motherboards have multiple socket sensors.)
Try AMD Overdrive, Core Temp, and Speedfan, and cross reference the results. You should be able to figure out which, specifically, is which so you can trust them.