I've been noting a number of threads over tha past many weeks citing complaints regarding reversed or doubtful teperature indications from Gigabyte motherboards. As Gigabyte doesn't host a forum, you may have to search around a bit. Have you flashed the BIOS?
I just downloaded Intel Thermal Analysis Tool from this thread...
This thing tells me the CPU is running @ 40°C. There has to be something wrong here.
For more information on C2D temperatures, check out: