Here are my system specs and their temps (Using Speedfan 4.37 and Everest 4.60.1500) - all while at idle:
790i SLi FTW Mobo - 85C
Q6600 Processor - Stock - 40C - All cores between 28C-36C
ATI Radeon HD 4870 - 1GB - see below three
(GPU Diode (DispIO) 50 °C (122 °F))
(GPU Diode (MemIO) 60 °C (140 °F))
(GPU Diode (Shader) 54 °C (129 °F))
640GB Western Digital - 32C
4 GB Corsair DDR3
When I run Speedfan and Everest they both come up with the same high temp.
I have tried reseating the heatsink/cpu fan and even put on arctic silver 5. I bought a new 120mm fan and attached it to the back, blowing out and took the old one and put it in the lower front blowing in.
When I check the bios it has my Board at High 40C's to 50C with the other 2 temperatures not exceeding 50C.
Any suggestions? If you need any more info just let me know.
It could be a phantom reading. Sometimes you have a sensor spot with nothing connected.
You do have a little fan on the chipset right? That is about the only thing I could see causing a high temp. all you other temps are good(to the point that it is hard to believe anything else is overheating in there)
Under the hardware monitor in the bios, see what it says and try turning off any fan speed control options if they are on.