Intel C2D stepping list
Look at that, there is only one E4400 stepping entry. Click on that, and it shows:
Thermal Design Power: 65W
Thermal Specification: 61.4°C
Core Voltage: 1.162V-1.312V
So the question is, is that thermal spec measured on the outside of the case in the center, or do they mean the temps as measured by the DTS inside the core? Because if it's the former, then I'm probably ok, otherwise, not.
Another interesting thing is that the core voltage spec seems wrong. CoreTemp reports my default vcore to be 1.325v, which is above the range that Intel lists, although not an unusual vcore in general for C2D chips.