Intel TAT / CoreTemp / IDCC all different temperatures....

[unclewebb]

I finally bought an IR Thermometer to do some testing with. I've posted some interesting information over on the [H]ard forum but unfortunately the site is down at the moment.

I have an early revision B2 E6400 which every program including TAT assumes a TjMax of 85C. Using my method of lowering the core voltage and lowering the MHz as low as they go I was able to remove the fan off of the OEM heatsink and get a very accurate temperature reading directly off the copper cone in the center of the heatsink. With CoreTemp reporting 21C, the measured temperature of the heatsink was 27C.

This of course is impossible. A heat source at 21C can't possibly heat up the heatsink to 27C. After this test and others I seriously doubt if there are any C2D processors with a TjMax of 85C. All mobile Core processors, Solo, Duo, Core 2 Duo, all have an Intel documented TjMax of 100C. I continue to believe that the Desktop Core processors also use the exact same TjMax of 100C.

DTS is still the best way to go but for those that are interested in an absolute temperature, I would only use software that assumes a TjMax = 100C.

Next step is to try and run the processor without a heatsink with only a highspeed 80mm hand held fan keeping it cool. If it's possible to run a C2D like this without the core temps going through the roof then I will be able to get a direct temp reading of the cores without a heatsink getting in the way, reducing the true core temperature.

Should have some interesting results by next week if nothing catches on fire!

[Prefixxx]

Curious about your findings unclewebb

Me also having problems with the understanding of my own E6600 temps.

Hardware :

- E6600
- Asus P5B-e
- Asus 8800 GTS 320 mb
- Antec NSK6000 (front 2x 92 mm fans, bottom 120 mm intake fan @ 800 rpm and back outtake 120 mm AC fan).

Temps are :

Ambient 21.3 celcius


- IDLE
CPU : 42
Motherboard : 40
Core 0 : 23
Core 1 : 23

(on the screenshots after a cold boot)

- STRESSED
CPU : 56
Motherboard : 41
Core 0 : 41
Core 1 : 41

As you can see the CPU temp is higher then Core temp.
Are those Core temps realistic with this Ambient temperature?.

I started a thread on Tom's Hardware asking about this and some of their members say that CPU temp is way to high (55 is max for Orthos) as I have +/-56).

Quote from another member @ Tom's Hardware

Dude, the CPU temp of 56-60 is what is reading accurately, your two core temps are the ones which are inaccurate and need to be offset. Read the C2D temp guide. By the way, your accurate cpu temp of 56 is too high, the guide explains that you should never exceed 55 with orthos, 60 with TAT.

..

What that means is your actually loading @56/71-71 <---> 60/75-75 which is too high. Stay bellow 55/70-70 using Orthos.

For @56/44-44 to be accurate or what ever, that would mean you are water cooled. By deductive logic, the 44s are then the ones reading inaccurately. 44 Tjunction doesnt make sense on Orthos unless you are watercooling, meaning it definately needs to be offset by +~27. I had to offset mine by +~25. Same boat as you.

As you can see and already sayed in this thread, it's get a bit (alot) confusing

-- Screenshots --

- - -

[kwalker]

Note the inconsistencies between the Tcase temp and core temp in the last two replies
This is on the rare side and related to motherboard bios revision and or software corruption.
Referring to Tcase as T-junction is just plain silly.
T-juntion (or TCC activation) is fixed and between 85 and 100 C it is not software readable but closes enough to reference the actual digital temperature reading which the software calculates for you.
A Tcase reading in the 50s under load is well within the thermal guidelines and a temperature of 60C max is fine. (The advice was incorrect)
I have no opinion of TAT that I can share being that its design was intended for the use in the mobile platform
The problem is the discrepancy where Tcase is higher than core temp.
This makes both readings unreliable.
Update your bios and use the motherboard reporting software to monitor your temps.
Perhaps this will resolve the issue but there are no guarantees.
Uncleweb……
You’re bold.
Just an opinion,
Using an IR thermometer is acceptable for cooking a Turkey or even approximating ram temperature but highly inaccurate for thermal analysis that refers to internal temperatures or at least Tcase which requires an appropriate heat sink to stay within the thermal design guidelines.

[blacksun1942]

56C is NOT TOO HIGH, whoever told you that you shouldn't exceed 55C is feeding you BS.

56C is WELL WITHIN NORMAL RANGE when running Orthros.

What that means is your actually loading @56/71-71 <---> 60/75-75 which is too high. Stay bellow 55/70-70 using Orthos.

This is meaningless.

...he says "your *accurate* cpu temp of 55 is too high"?? If 55C is accurate then you're absolutely within normal and safe limits. He has NO CLUE what he's talking about.

Trust me, you're fine.

[Prefixxx]

56C is NOT TOO HIGH, whoever told you that you shouldn't exceed 55C is feeding you BS.

56C is WELL WITHIN NORMAL RANGE when running Orthros.



This is meaningless.

...he says "your *accurate* cpu temp of 55 is too high"?? If 55C is accurate then you're absolutely within normal and safe limits. He has NO CLUE what he's talking about.

Trust me, you're fine.

Thanks for the confirmation for those temps
Still find it strange that CPU is higher then both Cores wich I understood should not be. Searched Google for an answer and didn't got any, but 1 thing it did notice me is that it occured on (most) Asus P5B boards.

Hehe when enabling PECI, I get lower temps for CPU (below the core temps). 16 degrees Celcius looks nice for CPU :P

[unclewebb]

Using an IR thermometer is acceptable for cooking a Turkey or even approximating ram temperature but highly inaccurate for thermal analysis...

When I first got this toy and started using it I was getting some very inaccurate results. The shiny copper cup at the center of the heatsink could not be read properly so I covered it in some thin masking tape to take the shine off of it.

After doing that, the readings I'm getting now are very consistent. I unplugged my computer and let it sit for over an hour. When I came back the temperature of this cone was exactly equal to the ambient temperature so my readings of this cone are accurate.

The only way I'll be able to run a C2D with the heatsink off is to have a hand held fan blowing cool air on it. At low MHz and voltage, my C2D is only putting out about 20 watts of heat so this is certainly possible. If I can do this and can get a stable CoreTemp reading then I might be able to go in with the IR gun and get a reading for comparison. If nothing else it will certainly be interesting! Worst case, I see a new E6420 in my future.

My old Pentium III lived through worse torture than this.

[unclewebb]

This is how software tries to determine your TjMax:

http://softwarecommunity.intel.com/i....aspx#30228327

"Next you have to assume that the Tjunction is 100 degrees Celsius and if bit 30 of MSR 0xEE is set then it is 85 degrees Celsius."

The Intel rep says at the end of this thread that this is NOT valid for Desktop processors but I think temperature monitoring software continues to do this.

I used CrystalCPUID to do a RDMSR 0xEE and my E6400 shows bit 30 is set.



I can understand TAT reading this bit since TAT was designed specifically for mobile processors and has never been updated for the desktop core processors but if CoreTemp and SpeedFan are using this method to determine that my processor has a TjMax = 85C then they are wrong. All of these programs are in complete agreement but that doesn't make them all right. Instead it makes them all wrong.

At idle if my heatsink is 6C above my reported core temperature then my reported core temperature is wrong. The DTS represents the hottest point on the core. The heat transfer from the core through the IHS, through the AS5 paste and through the copper heatsink should result in a lower temperature for the heatsink and definitely not higher.

Using a TjMax = 100C for my processor gives me a lot more realistic number for my absolute core temperature.

I believe that TjMax is a fixed value but the other guys on this forum could be correct and my TjMax might actually be 95C or some other number around 100C. If I can get the heatsink off I think the IR thermometer should get me some temperatures very close to the real core temperature.

All I know so far is that assuming a TjMax=85C for my revision B2 Conroe core processor is wrong.

Also keep in mind that I am only using the Intel OEM heatsink which certainly isn't the most efficient these days. I have a Tuniq tower arriving later today which typically results in even lower reported core temperatures.