There are two sensors on the Intel quad chips.
Each sensor is about 2 bits worth of silicon. You mobo has about the same amount of silicon that is used to translate the data from the sensors. If you built the system, you put them together for the first time. Did you calibrate them? (redundent question, there is no way to do that)
What amazes me is how often they are as close to accurate as they are. Looks like your second sensor may be read a little low.