I had similar issue before. All was needed is to remove the CPU cooler (whatever type you have installed), clean the thermal paste off it, put just one or two tiny drops of new paste and spread nicely, evenly in thinnest layer (you will even see metal under when it's thin enough) with the credit card (or any other plastic even thingy). Remember, thermal paste is not to make a seal between CPU and cooler, it is to fill the uneven tiny gaps on metal.
After I have done that my idle dropped from 43 to 29. Do I need to mention full load?
Also good thing is memtest, make a boot CD or USB (if you mb supports it) and run it until finishes at least 2 runs.
Hope that helps at least tiny bit.