You might want to check the accuracy of the software you are using to measure such things.
I know that Marcel Bresink, for example, recently introduced new algorithms to
Hardware Monitor to cater for changes in readings from some Intel processors that could lead to inaccuracies of as much as 15ºC . Given that Marcel is usually way ahead of the pack where such things are concerned you might want to make sure your own temperature monitoring software is both up to date and accurate.
Not saying this IS the problem, but it is worth considering, though in your case the apparent presence of hardware issues suggests that all might not be well with your machine in other areas.
Cheers
Rod