CPU temp vs Core temp?

[yiplong]

I have a P2 X3 720 BE CPU, the reported CPU temp is always about 5-6c above the core temps. Since the cores are the ones generating the heat, shouldn't they be a bit hotter than the CPU overall, so how come my CPU temp is hotter than the cores??

[shaithis]

The temperature diodes are notorious for being badly calibrated or just wrong.

I would truest the die temps before I trusted any temperature from a motherboard diode.

[woody_294]

Shaithis is right, they're probably not calibrated very well, but do bare in mind, there's more than just the cores under the heat spreader, PCI-E controllers, memory controllers etc.

There's always a couple of degrees difference between sensors at least, as long as none of them are hammering away in the red zone it isn't a problem.

Out of interest what board do you have??

[yiplong]

Gigabyte MA770T-UD3P. There is a sensor that always registers 79 or 80c. I wonder what it is. Maybe that's the NB chip? But its temp is pretty much constant, so I think maybe the sensor is defective.

[Uriel]

Core temps don't include the whole CPU die though. As well as the 4 cores (1 disabled on the 720) there is the CPU-NB (integrated memory controller and l3 cache). It runs at a different speed and voltage from the rest of the CPU and can get pretty toasty. Due to the die layout, if your 3 core temperatures differ more than a coupld of degrees, it's could be the influence of the CPU-NB (the CPU-NB is located on one side of the die, sitting next to 2 of the 4 cores. The other two cores are remote from it).

AMD's official support position is you should monitor the whole CPU temperature from the diode and not just the core temperatures.