there are more then one sensor in a cpu and on the mb. there are core temps. the cpu package temp that hardware monitor will show then the temp sensors on the mb. the mb temp sendor can be higher or lower then the cpu temp depending where the sensors is and if there a fan blowing air over the sensor. idle temps for an intel cpu will be 30-40c depending on the temp of the room and airflow and cpu thermal paste and the size and type of cooler used. good load temps...prime95 or a game is 50-70c. anything over 80c you start cooking the cpu. the cpu itself has a higher fail temp then 80c but if your rig hits that then your fan or heat sink falled off the cpu.