It's not uncommon for different software programs to get different results based on the reading from a silicon thermal diode or thermistor (temperature variable resistor). Which is either under the cpu in the center of the socket, and one is also built into Athlon XPs and P4s. I don't know which sensor the A7V8X uses, though I would hope the ondie thermal diode built into the Athlon XP.
Basically a thermal diode is very precise in tracking changes in temperature, but deriving the exact temperature itself is more difficult. The same is basically true for a thermistor, the temperature change vs change in resistance is pretty accurate, but the initial resistance at some fixed temperature is not nearly as precise. Generally though, for a thermal diode, the error will be about the same for any measured temperature. (I.e. If it reads 40C and the actual temp is 45C, it will probably read 45C when the actual temp is 50C.) For a thermal diode you can get very accurate results, but you generally have to obtain a base voltage reading at some known temperature. This will vary a bit from diode to diode, which means that if you just take the average reading of a bunch of diodes some will be more accurate than others.
