55c at idle + loud fans, I think you should reapply your thermal paste. What are your mobo socket temps? I wouldn't be able to tell you where you would find that as I tihnk its different on each mobo. For example mine is called TMPIN0 according to hwmonitor. It should be within 5-15 degrees of your cpu temp.
About the bios, it should be getting its info from the proc via DTS and should have other sensors for socket/nb/sb/etc. I mean DTS isn't a new tech, its been around since C2D IIRC,