i'm not sure if the temistors in the board touch the CPU or if the MP's have something to read it's own temp, I looked on the the specs for my board and it didn't say, this is the board I have.
MS-6501
edit: just looked up the specs on AMD's website, the MP processor has an internal thermal diode on the die, not sure if the bios is monitoring the temp from that or a sensor on the board itself.