What is the difference between CPU Temperature and Cores Temperature

[channabasanna]

Hi All,

I have attached the Snapshot of my System Temperature below.

*www.freeimagehosting.net/uploads/0b0faca04d.jpg

My RIG is in my signature.
I used my ASUS Probe II, PC Wizard, Core-Temp softwares to get my System Temperatures.
I have highlighted the Core Temperatures in Red Rectangles, and the CPU Temperature in Blue Rectangles.

Earlier with Stock Cooling from Intel, ASUS Probe II used to show temperature of 45C, now few days ago i updated my Motherboard BIOS, now it is showing 25C for CPU with OCZ Vendetta 2 Cooler.

Can i know why is there much difference between CPU Temperature on a whole, and individual Cores.

Also is my System Temperature under limits.

 

[Power_user_EX]

Atlast a good question!

Now all C2D and some olders ones have 2 temp sensors on the die.

Intel does not document much on these sensors.
One measures the tCase i.e-> CPU temp and other is to measure the tJunction i.e-> Core Temps.The Safe temp ranges for both r quite different. It is high for tJunction and low for tCase.

About tCase :
tCase is sensed on the CPU case by the thermal diode which is analog and this analog reading gets convrted to digital by th Super I/O chip and gets calibrated by the bios.

Now, About tJunction :
tJunction is sensed inside the 'actual' cores by the thermal diodes as an analog level which is then converted to digital by the digital thermal sensor right on the CPU itself.
These vals r manufactrer calibarated.

tJunction is always higher than tCase.
Intel documents the maximus tCase temp in its specs.

Typ reading for Quads frm my experience :
Danger : (using intel burn in test)
tCase =72
tJunction= 80-80-78-78
Hot:
tCase=66
tJunction=73-73-71-71
Normal/safe :
tCase=55-60(or below)
tJunction=68-68-66-66
Cool:
tCase=23(& below)
tJucntion=35-35-30-30

But in practice actual differnce between tCase and tJuncton is more than 10C - atleast for me!Also the temps of Core 0 and 1 is higher than core 2 and 3 - again atleast for me.

My temps @ 3.02 Ghz for Q6600-G0 using Thermalright ultra 120 extreme:
*img254.imageshack.us/img254/337/mytempyp2.th.gif*img254.imageshack.us/images/thpix.gif
*g.imageshack.us/thpix.php