My guess (and it is only a guess) is the old BIOS was not reporting the temperature correctly. 27°C (80°F) sounds unfeasably low for any CPU unless you are in an air conditioned room (around 21°C, 70°F) and have a monster heat sink. 48°C (118°F) sound far more likely, especially if you've got a standard CPU cooler on a standard (i.e. not black edition) CPU.