I'd try the following: download and run realtemp. Unzip and run it directly from the extracted folder. As far as I know no installation is required. Once you see the sensor readings, go to the configuration tab of speedfan, then temperatures, and look for the corresponding values. Rename and configure for display accordingly. Of course you'll read the actual 'on-die' core temperatures (t junction). In my opinion this is anyway the better way to monitor your CPU temp since you don't need to bother about adjusting offsets to get a proper reading for t case.
Once you have found the right readings, you could google for max temp specifications for your CPU so you'll know if you're in the safe area or not.