Speedfan picks up a lot of sensors that aren't necessarily working so there are always some junk readings. (Temp2, likely Fan1, and maybe Fan3)
The picture you took tells me you weren't stressing your processors so the temps reported aren't that useful.
Do you have
prime95?
If not get it and run two instances, one for each core, let them run for a couple of minutes while you watch the numbers and see which temps elevate. Also fiddle with the fan speed and see which ones move.
Temp1 is probably your NorthBridge.
Temp3 is probably your case temp. (the temperature inside your computer case)
The Core temp is probably your CPU.
All you need to watch for is to keep the temperature readings from exceeding ~60C. Any other use of the readings is futile since the temperature probes being used are too inaccurate.