Core#0 & Core#1 not having same max load temp

I just have switched my T2500 processor to T7600 processor. When I run HWmonitor and Orthos, the temperature reading while on max. load for core#0 and core #1 differs by 2-5 deg. F (1-3 deg. C). Is this normal? Or is there something wrong with my heatsink, maybe I did not seat them right (I think I did). Also maybe I used to little AS5 thermal compund on them (I think I placed just enough).

 

Its normal . . .

 

It's normal. It is because a dual-core processor has two equivalent "dies" and the temperature sensor for each die is located in the same position as the one in the other die (the temperature diode in each processor die is not in the center of that die, but more off to one side). So basically, one core's temperature sensor is near the center of the die while the other core's temperature sensor is near the edge of the die, since each core is exactly the same and they are etched side by side into the die. The core whose temperature sensor is closest to the middle of the whole die will read the hottest temperatures for obvious reasons

-J.B.

 

The power consumption (and therefore heat) of individual CPU cores can differ due to manufacturing variations. I have a 4C difference in the temperatures of the two cores of my P8600.

John

 

I wouldn't worry to much. I have the T9300 and mine can differ by over 12'C at idle alone.

Seems to me that core #0 is always hotter; I rationalize this that windows always loads core #0 first so it will always be hotter. (Anyone know if this is relevent at all?)

 

mine are always no more than 1 or 2 degrees different. they both fluctuate

 

My core #0 is the cooler one.

John

 

it's also possible that the heatsink is not 100% flat and therefore not applying the same pressure on the cores all the way across. I remember that was an issue with the previous AMD x2's and Intel CPu's (desktop mostly though).

 

Ok, thanks everyone! I guess its just normal.
My friend also has a T8300, and his core#1 is higher.

 

Theory failed.

 

My core #0 is hotter. T9400.

 

The thermal diode which reads the temperature of the cores are not located on the center of the die, so the thermal output is going to be different no matter what. The thermal diodes are usually located on one side of the core, so when two cores are sandwiched together it looks like this (core, thermal diode, core, thermal diode)
so the innermost thermal diode will always read a higher temperature because some heat is transferred from the other core as well.

oh powerpack, what did you do this time

K-TRON

 

Hey K-tron, do you know why the loads aren't the same. When I stress the CPU, one core goes to 100% right away, the other goes up to 100% after a second or so... sometimes when loading firefox one core is stressed like 20% higher than the other.

 

It may be a little while before he can answer : He went OT in OT (again).

John

 

you can only see the load of the CPU cores maxed together in multi-threaded programs and games.

try wPrime 1.55 ... its the most basic but stable multi-threaded CPU benchmark around (even NBR has used it in their reviews).
- make sure to set the Threads to the number of Cores your CPU has.

as for CPU core temps. Min is around ~10C difference at any time from Core 0 to Core 1.

Its normal.

 

The thermal diode is in the hottest part of the chip (so near the main parts of the CPU and away from the cache). This is to reduce the chances of damage during sudden heat spikes, if the diode was in the centre of the chip and the heatsink came loose the main core will heat up before the cache but the diode would not sense this until it was to late (aka AMD XP chips).

Differences in temp come about because of imperfections in construction. There are different things like slight changes in leakage current or differences in track thickness on the interconnects that can heat or cool more. There can also be differences in how well the heat is transported away from the chip by the heatsink or IHS (on desktop chips). All of these will change the heat produced or dissipated by the core of the CPU.

 

At idle: 41-37-40-42

Core #1 is a slacker so he is generally 6-7 degrees cooler under load.

 

LOL. It is as certain as Randy Moss opening his mouth.

 

Running HWmonitor, there is another temperature reading under TZO.
TZ0 reading is under ACPI. It give the same reading as my mobilemeter temp reading. It is usally different from my core reading, varies between 6C (idle)~2C (max load). Does anyone know where the TZ0 sensor is located?
BTW, my notebook is Asus Z96J/S96J (Intel VBI) 945PM chipset.