Does anyone out there use speedfan?

Speedfan gets its readings directly from the monitoring chip and not filtered through the bios. As a result it reports all the readings that the chip is capable of regardless of whether there is a sensor there or not.

So first find out if any of the sensors are actual sensor or just phantom readouts. Hovering the cursor over each temp should tell you the min and max, if the numbers are the same, ignore that temp, because it's a phantom readout.

Just open the config settings and uncheck those readings.

CPU is normally the CPU temp, the actual casing of the CPU core.

CORE temp would be the actual inside temp, the silicone CPU temp.

AUX: There is no standard for sensor registers layout, so the AUX temperature could show the temperature of the CPU or the motherboard, or might be a non-connected wire of the sensor chip, and so it could show a bogus value.

In my rig, when I slow the Northbridge fan down, the SYSTEM temperature goes up in SpeedFan. So I'm assuming that's what it is.