Sandra CPU temps

How does Sandra get the temp of the CPU under the CPU information thing. I know that my motherboard came with 2 programs which will tell me the CPU temp, and they both read from the sensor under the socket. They both give me one result, but Sandra gives me another. I am running the below system (however right now i have it back down to 1100MHz stock speed) and Sandra tells me that my CPU temp is like 45C, and the two programs are telling me 33C. It would make sense if Sandra was reading the temp from the actual core, but isnt the XPs the only AMD chip that does that, or am i mistaken and the Duron do it too? Any help would be wonderful.

Thanks.