I am beginning to use Speedfan.
I was wondering what is the difference between Temp1 and Core shown in SpeedFan? Whose temperature is more important?
TBH it's difficult to say. My guess would be Temp1 is the temperature returned by the thermal diode sensors just near the heatsink & Core would be the temperature of each core. Both would be critical. As for northbridge/southbridge temperatures - Speedfan should return them if suitable sensors are available.
Else check out HWMonitor.