this is such bull****.. i don't know which one to believe!
coretemp says 77-80 degrees idle.
HW monitor says 29-30 degrees idle
i am going to believe in HWmonitor since it correctly got my GPU temperature right
You can also try Everest Ultimate, it gives you most information you would need even using the 30-day trial version.
You must have a very good CPU cooler, but I do believe the 30C idle, and 40C under load with a slightly elevated voltage is very good.