NF7-S/AN7 temperature offset?

How off are the temperature readings i am getting through speedfan and mbm5. Electron Chaser and solidsnake said that they are off by about 6-10C.

Is there any place where i can read more about this?

Is it worth it to offset the termperature readings i get through speedfan because i think it is possible in the configuration menu.

Thanks

-Ty