If it's an L2 stepping E6400, then both TAT and CoreTemp 0.95 will both report temps 15C higher than SpeedFan 4.32 or CoreTemp 0.94. The first two use 100C as the Tjunction value and the second two use 85C as the Tjunction value.
For the AS5 vs. ASC question, I'd refer you to what this AS...