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Dual Core Temps Difference?

Posted: Sat Feb 24, 2007 8:56 pm
by Sparky
Is it normal to have different temps on each core on a dual core cpu? I have an Intel E6700 and core 1 runs 4 degrees Celsius (or greater) than core 0 when I’m running Intel Thermal Analysis Tool (TAT). Makes me wonder if I need to remove and reinstall my heat sink and fan. Perhaps I don't have the artic silver spread evenly???
Has anybody else had this occur?

Posted: Sun Feb 25, 2007 6:33 am
by super_cool
As far as I think it's normal.I have noticed this too.I think if they don't run too hot or if they are not showing temps out of warning level,there's nothing to worry about.

Posted: Sun Feb 25, 2007 8:33 am
by Sparky
Thanks. I have noticed on task manager that CPU 1 seems to show more use than CPU 0, so perhaps this is the reason.

Posted: Sun Feb 25, 2007 9:42 am
by Zoogle
Also, Intel's dual cores are technically two dies on a single chip. So one die could have more voltage leak than the other one.

Posted: Sun Feb 25, 2007 9:54 am
by kenc51
Zoogle wrote:Also, Intel's dual cores are technically two dies on a single chip. So one die could have more voltage leak than the other one.
He's using a E6700 not a Pentium D. The C2D chips are two cores on one die! (ie. Native dual core)

It's normal for each core to have different temps, even under full (equal) load. I wouldn't worry about it!

Posted: Sun Feb 25, 2007 10:59 am
by SAMSAMHA
almost all of my dual core (both intel and amd system) shows about 5 degrees diff between the 2 cores, it's normal/

Posted: Sun Feb 25, 2007 12:00 pm
by Sparky
Thanks again for all the feedback. I also have an AMD 4800X2, but I've never able to verify the temps on individual cores utnil I used TAT.

Posted: Sun Feb 25, 2007 12:34 pm
by werty316
Will the TAT allow you use an AMD CPU with it?

Posted: Sun Feb 25, 2007 1:03 pm
by T-Shirt
werty316 wrote:Will the TAT allow you use an AMD CPU with it?
Yes, but it instantly fries the CPU :lol:

Posted: Sun Feb 25, 2007 1:09 pm
by dicecca112
Coretemp does the exact same thing that TAT does but it works with newer AMDS and C2Ds

Posted: Sun Feb 25, 2007 1:10 pm
by Sparky
Not sure about TAT and AMD cpu's but not willing to risk it.

Just removed, cleaned and reinstalled my heat sink & fan (Zalman 9500) along with some Arctic Silver 5. Still see difference in temps but at least it puts my mind at ease.

Posted: Sun Feb 25, 2007 1:11 pm
by Sparky
Core Center shows cpu usage and temp but I'm not sure about indiviual cpu temps. Still, I have always felt better knowing what my temps werre rather than assuming all was well.

Posted: Sun Feb 25, 2007 1:59 pm
by SAMSAMHA
not TAT, but I see the diff in everest.

Posted: Wed Feb 28, 2007 2:15 am
by largon
Too bad even CoreTemp can be proven to be very innacurate.
It's atleast 8ºC off.

Posted: Wed Feb 28, 2007 7:37 am
by dicecca112
how is it off? How can it be off it reads the cpu's internal temp diode, the same temp diode that Intel reads

Posted: Wed Feb 28, 2007 9:32 am
by largon
dicecca112,
It's all about the accuracy of the DTS in the die.

I noticed something was wrong with CoreTemp one day when I plugged a temp sensor in my digital multimeter and got 23ºC for ambient. CoreTemp was giving idle temps of 19/20ºC core#0/core#1 (E6600). Then I rigged the sensor on top of of the CPU waterblock right next to the lineout tube: DMM gives 27ºC.
Thus CoreTemp is off atleast by 8ºC.
But likely the offset in CoreTemp is >8ºC in reality because the top is likely not the warmest part of the waterblock.

The DMM is 1.5ºC accurate.

Posted: Sat Mar 10, 2007 2:29 am
by SLi_dog
largon wrote:dicecca112,
It's all about the accuracy of the DTS in the die.

I noticed something was wrong with CoreTemp one day when I plugged a temp sensor in my digital multimeter and got 23ºC for ambient. CoreTemp was giving idle temps of 19/20ºC core#0/core#1 (E6600). Then I rigged the sensor on top of of the CPU waterblock right next to the lineout tube: DMM gives 27ºC.
Thus CoreTemp is off atleast by 8ºC.
But likely the offset in CoreTemp is >8ºC in reality because the top is likely not the warmest part of the waterblock.

The DMM is 1.5ºC accurate.
Hmm, you may have received a CPU with dodgy on-die temp sensors but I doubt it.

Also, CoreTemp may seem inaccurate for your CPU but that doesn't mean it's wrong for eveyone elses.




To the original poster, I do find it surprising that you're getting different temps at full load. From my experience, though they may idle at slightly different temperatures, the max load temps will be the same.

This is similar with the QX6700, which is two dual cores in the one CPU, where you can get differences between cores but generally core#0 and core#1 (CPU1) will have the same load temp and core#2 and core#3 (CPU2) will too. There may be a difference between CPU1 and CPU2 though, sometimes by 5C or more.


Maybe download Orthos and run the Small FFT test for 10 minutes and see if the temps end up being the same. If not you may need to make sure your HSF is applied with equal pressure.

Posted: Sat Mar 10, 2007 9:24 am
by Sparky
I just ran Stress Test v1.0 for 2 minutes and both cores still show 2-4 degrees C difference. Got close a couple of times, but then differed again. Not too worried about it because I've read more and see it appears to be normal.

Posted: Sat Mar 10, 2007 10:44 am
by kenc51
IT'S NORMAL FOR BOTH CORES TO HAVE DIFFERENT TEMPS, EVEN WITH EQUAL LOAD ON EACH CORE!!!!!!!