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

[joebuffalo]

So...When someone see DTS=0 that doesn't mean his cpu is at 85C.
He may have 60C...or 70C or 80C or 90C.

Right ?

That is the gist of it.

[unclewebb]

joebuffalo: Thermal Monitoring is enabled in my bios and Rightmark shows that both TM1 and TM2 are enabled.

Here's some more high temp experimenting:



What I found interesting today is that once again TAT went red and showed Thermal Monitor Active when CoreTemp got up to DTS=2 but TAT never reported more than 79C to 80C even as I held it at the boiling point for several minutes.

Here's a partial look at the TAT log:



The other day a CoreTemp reading of DTS=2 was getting me TAT reported temps of 83C and today only 80C for the exact same DTS value. There doesn't seem to be too much logic when a computer program varies its output depending on the day of the week or who knows what.

[joebuffalo]

From my experience, TAT tends to read a degree or two below CoreTemp

In the last screen shot you posted (previous page) you had TAT=83 when DTS=0

[unclewebb]

I find it odd that my first screen shot on the previous page, TAT + DTS = 85 and then on the second screen shot TAT + DTS = 83 and now this last screen shot TAT + DTS = 82.

If TAT is using the same DTS value that every other program is using then on the same computer, it should be consistent from day to day but it's not.

I can understand when there are timing differences when a sensor is read but in each case I tried to stabilize the temps before going for a screen shot.

Some people trust TAT because it has the nice Intel logo on it but I find that CoreTemp is a lot more consistent.

[joebuffalo]

Agreed. Reason I don't like TAT (for reading temp) is because it will not display DTS directly and we do not know how it using DTS to calculate the absolute temperature. Two unknowns

[RealTelstar]

I'd like to bump this very informative thread

[Coffee29]

This is probably the best thread on desktop core 2 duo temperatures on the web. I spent a week trying to find out why my temps were reading 15 degrees one way or the other depending on the program. My search led me to the intel forums, product documentation, and to the "temperature guide" from that other forum, Im sure you know the one.

I added up all of the facts and compared them to what was being said and I realized that most of the info on the web about reading core2duo temps is misinformation. I finally concluded that there is NO way to get an absolute temp on these desktop chips, but I also realized that this is ok because one can accurately utilize DTS and temp readings on former chips probably were not that accurate anyway. DTS is act ually a great thing.

IT was at this point that I googled DTS and C2D chips and found this thread. It was refreshing to see you guys coming down to the very same conclucion...you are right on....everyone needs to embrace DTS!

[Coffee29]

a few more things that I think need to be restated due to all the misinformation, please correct me if I am wrong:

1. TAT is NOT intended to be used with desktop C2D processors and WILL NOT give you accurate temps because temps for desktop c2d cannot be known. Mobile c2d's have a set tjunction and TAT works fine for them.
2. The word "Tjunction" itself only applies to mobile c2d's.
3. The whole reason programs are giving the 15 degree variance is because they are assuming tjunctions of 85 or 100...refer to number 2--->tjunction DOES NOT apply to desktop c2d's.
4. I am not sure about this but I think tjunction DOES apply to quads---> correct me if Im wrong. If it does and if they are documented at 100 TAT would work just fine I would assume.
5. It seems that the consensus is that DTS readings, which can be obtained from the newest coretemp are safe if above 20 or so, generally speaking.
6. Coretemp confuses the issue with its even mentioning "tjunction", this word and its use needs to be deleted from the entire program and the program should only read DTS. Even when you set it to read dts it states x dts to tjunction....this should instead read so x dts to TCC. TCC is the trip noted in the intel documents.
7. Changing the tjunction in coretemp should not affect the DTS, it looks like it would and for this reason the program is confusing to mnay...so remember DTS is not a calculated number, it is simply a readout of what the diods are reporting.

Please correct me where I went wrong, but from the forums around town it seems like there still is A LOT of confusion over this.

[redrol]

This thread is awesome. I have embraced DTS.

[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.

[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.

[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.

[RealTelstar]

Considering simple matters as the ambient temp, frequency and cooling that I have, I'm pretty confident of my assumptions.

coretemp 0.95 reports the following:
core0: 31&#176;C (delta 54&#176;C)
core1: 28&#176;C (delta 57&#176;C)
read interval 1000ms

My ambient is 21&#176;C measured by analogic quality thermometer. The assumed TCC is 85&#176; (by coretemp) and it seems accurate to me.

[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]

The assumed TCC is 85° (by coretemp) and it seems accurate to me.

It used to seem pretty accurate to me too until my IR thermometer proved that it can't be 85C.

The new Tuniq just arrived. It transfers heat better than the OEM cooler so the core temp readings at idle, based on TjMax=85C, should decrease and look even more ridiculous.

At 1200 MHz and 1.100 volts at idle, my OEM heatsink goes from 22C to a steady 62C with the fan disabled. Those little cores in there are putting out a huge amount of heat even at those low settings. The DTS is always reporting from the hottest part of the core so I think people are under estimating the true core temperatures.

Even with the computer sitting in Stand By mode the cores put out enough heat to raise the OEM heatsink by 6C above room temperature.

[joebuffalo]

Let's try to keep this thread on topic folks.

I think anybody new to this thread should read the ENTIRE thing a couple of times before posting.

Let's not turn this into a 'help me figure out my temperatures' thread. Start a new thread if that's why you are here.

[joebuffalo]

It used to seem pretty accurate to me too until my IR thermometer proved that it can't be 85C.

I told you that low voltage / reduce multiplier test which proved your processor had a tj_max of 85 was not kosher.

I ran across that hardforum thread the other day but have not had a chance to read it yet. I see it is not accessible right now.

I continue to be impressed with all the abuse you put your processor through so that we may all better understand temperatures.

[RealTelstar]

Hmm... perhaps I should invest in a thermometer

[unclewebb]

I told you that low voltage / reduce multiplier test which proved your processor had a tj_max of 85 was not kosher.

You were 100% right joebuffalo. My previous test seemed like a good idea at the time!

It has come in useful though. That is where the biggest temperature difference is found which proves that the accepted TjMax=85C simply isn't right.

SuperKeijo on the [H]ard forum used my test and was able to lower his core voltage down to about 0.69 volts and get his C2D to run at 600 MHz on his DS3 board. It became very obvious that TjMax=85C was not right for him either. He got things started by using an IR thermometer to confirm his numbers so I picked up a Fluke 62. I calculated at the reduced MHz and voltage that his C2D is likely only consuming 9 watts so he might be the first to pull his heatsink off for some true core temperature measurement.

Hopefully by early next week we'll all learn a little more. Either that or I'm going to have the first C2D keychain on my block.

[joebuffalo]

You are a gentleman and a scholar. And a CPU abuser!

[unclewebb]

One thing you can also use the CrystalCPUID MSR Editor program for is to read your DTS directly.

The raw DTS data is located in IA32_THERM_STATUS which is located at 0x19C.



Bits [22..16] contains the DTS info. To extract that in the above example you chop off the 4 least significant zeros to the far right in EAX. The number 28 is the DTS. 28 hex = 40 C so on this core I am 40 degrees away from TjMax whatever that turns out to be. You can use this program to read this data for any core.

It confirms that CoreTemp is reading this value and displaying it correctly in real time. The TAT reported numbers are not always consistent with the DTS.

Location 0x19C is used in ALL Core processors, Solo, Duo, Core 2 Duo, Quad and I believe it was first used in the Pentium 4 Prescott series but I don't have one of those to confirm. The 85C TjMax number might have actually originated from the P4 era.

[Miwo]

wow, had no idea my thread was still alive and kicking, I hardly visit this section of the Intel Forums :p

Very nice to see that many of you are testing/investigating and finding out a lot of new information on this matter. Keep up the good work!!!