Posibly incorect temp reported by motherboard sensor ?

[wako]

I have an GA-7N400-L motherboard and i was told that the cpu temp sensor from the motherboard is the fault for the 65C temp on a Sempron 2600+ without overclock.
Are there any known issues with this kind of motherboard/sensor?
I've touched the heatsink under the fan and it doesn't seem that hot. What can i do to measure the real cpu temp ?

 

[kizuki]

Check if your CPU is running at abnormal voltages using tools such as CPU-Z or if your ambient case temperature is above 45C. Airflow is important in your case.