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

[unclewebb]

Sorry to disappoint. Not only were there no flames but this heat baked E6400 with the new Tuniq is running better than ever. More proof that you don't have to worry about overheating one of these things even if the heatsink accidentally falls off!



Anyone who goes to Google to learn about C2D temperatures will sooner or later end up here so I think it's good to have some more facts which they can interpret as they wish to come to their own conclusions.

So far the E4300 being tested with a different IR thermometer is showing temperatures similar to what CoreTemp 0.94 is reporting which uses an assumed TjMax=85C.

[joebuffalo]

Get a copper rod. Place one end in ice water. Heat the other end with a blow torch. There will be a thermal gradient along the bar. Yes? One end will be very hot, one end will be cold. In the middle of the bar, the temperature will depend on the location along the length of the bar.

We have the exact same thing going on here.

Let's neglect all the thermal conductivity killing interfaces that are present between the core and the heatsink for the moment. Let's assume we have a perfect heat conduction path from the core to the air.

You have a heat source (the core)
You have a heat 'sucker upper' (the ambient air)

There WILL be a thermal gradient along the path from the core to the ambient air. The underside of the IHS will be hotter than the top side of the IHS. This is a fact of life.

I *think* you may be getting caught up by assuming a steady state (where everything is the same temperature) is reached. But it is not. Heat is always flowing from the source to the sink. As a result, there will always be a thermal gradient. As such, you are not measuring the core temperature when you measure the temperature of the IHS.

[unclewebb]

There WILL be a thermal gradient along the path from the core to the ambient air. The underside of the IHS will be hotter than the top side of the IHS. This is a fact of life.

I was faced with the same argument when I was taking temperatures of the copper cone at the center of the OEM heatsink. I agree that there is a gradient but the temperature being reported by the IR thermometer has not really changed.

I removed the heatsink so I could get a reading off of the IHS directly which takes the copper heatsink and the TIM out of the equation but the temperature results didn't significantly change. There was less than one degree difference when measured with the IR thermometer compared to when I measured the core temperature by measuring the other side of the copper heatsink.

[unclewebb]

joebuffalo: The C2D is individually calibrated on the assembly line. What likely happens is the processor is put into a socket and fed a minimal amount of voltage and run at a slow MHz similar to what I'm doing. SuperKeijo had no trouble running Orthos with his heatsink off because his motherboard allows him to run at a lower voltage than I can. The temperature can then be checked on the assembly line, likely with an IR thermometer or something similar and compared to real time readings from the DTS. Any necessary offset to correct the DTS to the measured temperature of the processor could be programmed into an on chip PROM type of memory which can't be changed later by the user.

My method of trying to read the core temperature with an IR thermometer might not provide me with the true core temperature due to the temperature gradients that you've mentioned but this method might be quite similar to how Intel calibrates their processors during manufacture. These are just my wild guesses based on nothing.

It really doesn't matter though. DTS is still king that no one can argue against.

What I do know now is that for my processor, when TjMax is assumed to be 85C, CoreTemp 0.95 reports absolute temperatures that are exactly equal to the temperature of the outside of my IHS as measured with an IR thermometer from about 45C to 85C. That may not be the ultimate true, blue core temperature but the CoreTemp reported absolute temperature number has plenty of meaning to me.

Testing has been fun. Thanks for all of your input.

[abe786]

Excellent thread guys..very informative
I have gone through all the testing which you did unclewebb..I've concluded that speedfan 4.32 and coretemp 0.94 both report the correct temperature for c2d's since they assume TjMax of 85 degrees which you're testing have resulted....so is that correct and I can breath easy by just noting there values...i own an c2d E4300 proccessor myself btw..

[joebuffalo]

Excellent thread guys..very informative
I have gone through all the testing which you did unclewebb..I've concluded that speedfan 4.32 and coretemp 0.94 both report the correct temperature for c2d's since they assume TjMax of 85 degrees which you're testing have resulted....so is that correct and I can breath easy by just noting there values...i own an c2d E4300 proccessor myself btw..

NO!!!!

You missed the entire point of the thread. Just use CoreTemp 0.95 and check out the DTS readings directly.

Even if you agree with all of unclewebb's testing, HE DOESN'T HAVE AN e4300!

[Coffee29]

i have an e4300 and you CANNOT go by the temp readings. Go by the DTS reading on core temp 95. The temp programs assume variables that are not documented and may not even exist, DTS is documented and is accurate.

[abe786]

NO!!!!

You missed the entire point of the thread. Just use CoreTemp 0.95 and check out the DTS readings directly.

Even if you agree with all of unclewebb's testing, HE DOESN'T HAVE AN e4300!

Yes, i've gone through the most of the thread and I do agree that DTS values is the way to go, but i wanted to find the safe temperature operating range for my CPU, since i was wanting to find out max overclock i can get with tempratures staying under control to prevent any long term damage...how can I do that with just DTS values, like for c2d its written that it shouldn't temprature shouldn't exceed 61 degrees for safety of the CPU...so to calculate it, I believe I need the TjMax value...

Unclewebb does mention that e4300 does have TjMax of 85 in post#176 (maybe he's borrowed that result from the hardforum guy whose also testing the CPU with IR thermometer)

[Coffee29]

the documented c2d temp of 61 degrees is an absolute temperature. This information is 110% useless to you in determining your safe zone for OCing because it is 100% impossible to ever determine an absolute temperature. Moreover, discussing tjmax makes little to no sense. The DTS number is a value that tells you very accurately how far your chip is from TCC activation. Temps guessed off of this are at best relative.

A good way to stay safe is by keeping your DTS over 20-30 in my opinion. Also use your fingers, check your ram, northbridge and HSF. Also make sure your system is stable, crashing is a good sign it is too hot.

What OC do you want and what cooler are you using? I didn't take my e4300 over 2.4 for a 24/7 OC on the stock hsf. With my new scythe mine I'll probably do a 3.0 24/7 OC.

Above all else, instead of attempting to use relative temps arrived at by guessing variables, skip the guesswork and learn to use what they are relative to--->the DTS

[abe786]

^^I'm running with stock cooler for now and OC is same as urs ie 2.4g, i get 22 as max DTS reading w/ TAT full load running on both cores...I will be getting a better cooler in coming weeks, with that I plan to run around 3.0ghz 24/7, maybe even more, if things are favourable...its a week 41 chip

By the way, the 20-30 DTS reading would corrospond to 65-55 coretemp 0.94 reading, so it may/may not be correct reading, but target's the same

[unclewebb]

TjMax exists for all processors but without this number being documented by Intel, all software is left guessing when it comes to reporting an absolute core temperature. If you don't want to invest in an IR thermometer and risk damaging your processor by running it naked and if you really want to see an absolute temperature number then I'd use software that assumes TjMax = 85C like SpeedFan 4.32 and CoreTemp 0.94 do. This is only for the Core 2 Duo and not the Quads and don't use this number to compare your results with anyone because they might be meaningless.

If you want a number that is 100% accurate, documented and guaranteed to have some meaning when it comes to C2D temperatures then stick with CoreTemp 0.95 which can be set to report the DTS directly, in real time, without any further bastardization of the number.



The Core 2 Duo has a huge amount of head room and there are only two things you need to be concerned about.

#1) Throttling. When a C2D gets too hot it will throttle and slow down which no one wants to happen. My E6400 doesn't start to throttle until DTS=2 which is far hotter than what 99.999% of people run their cpu at so it's not really an issue, especially if you're overclocking.

#2) Stability. If you can run Orthos for 4 hours and if your processor is not throttling then you've got a pretty good system that will be able to run most real world applications without any problems. If you are Orthos stable and not game stable then you should concentrate on your GPU and making sure it is not over heating.

You're CPU is going to need more temperature headroom the more you overclock to maintain stability. Here's what my E6400 needs.

3200 MHz ~ 1.30 volts ~ DTS=5
3400 MHz ~ 1.40 volts ~ DTS=15
3600 MHz ~ 1.50 volts ~ DTS=25

Those voltages are approximate Orthos load voltages and the DTS values are approximately how much headroom I need to maintain stability. Everyone knows that as the MHz goes up you have to use more core voltage to maintain stability but I was a little surprised to find out that there is also a direct relationship when it comes to temperature. You need more temperature headroom the faster you go and reading the DTS directly is the most accurate way to monitor that.

[tal0n]

Oh! unclewebb thanks for sharing...

I really suspect this, thats the reason I can not hit 3600 Mhz in my quadcore because the diference at 1,55 Vcore is no more than 15 º to Tjunction.

My Q6600 temps at load with 4 primes is 75º 75º 71º 70º at 8 x 400 = 3200 Mhz. That´s with thermalright Ultra 120 eXtreme.

That temps are at 1.375 VCORE set in bios with case closed, only one fan in Ultra 120 at 1400 rpm. I will try 3400 Mhz I think I can hit with only 1.425 VCORE in bios but my temps are near 80 º.

My temps are correct? Or is someone obtaining less.

Thanks

[joebuffalo]

tal0n, how are you obtaining those temperature measurements?

If you just reported DTS we wouldn't have to ask that question.

[Grinch]

so is this ok?

[joebuffalo]

A DTS of 44 is completely safe.

[tal0n]

tal0n, how are you obtaining those temperature measurements?

If you just reported DTS we wouldn't have to ask that question.

That's my temperature obtained with core temp but not DTS. DTS must be setting in core temp to show how much temp is far from TJUNCTION.

If I have a 75º temp in my hottest core I have a DTS of 25º because my TJUNCTION in core quad is 100º.

cya

[vera]

Hi, I bought a E6400 "L628B103"... This cpu is nice O/c'er , I use it 3500mhz def. vcore , and my cooler is TT bigtyphoon , but When I run the orthos small fft , it's up to 80 C !, before I have a E6420 and I used it 3.4 ghz and it's never to pass 60C ? I can't understand ?? please help !

[joebuffalo]

vera, READ THE THREAD. Your absolute temperature are meaningless.

tal0n, if you are running at stock voltage, DTS=25 is a good number. I personally am at 30 but would not have a problem running at 20 one of these days.

I think unclewebb has shown us that you are OK as long as your processor is stable and you have just enough DTS that you don't start throttling.

BUT, just because the systems is 'OK' doesn't mean that you aren't putting extra wear and tear on the CPU. So leave some a margin with a bit of DTS if you want your processor to not have any problem down the road.

EVERYBODY, PLEASE STOP WITH THE "My processor is at 80-C. Is that OK?" POSTS? THEY ARE POINTLESS IF YOU WOULD JUST READ THE THREAD. Please don't turn this informative thread into junk.

[tvdang7]

so whats the verdict? im in a dilema on which temps to trust cuz core temp is like 15 degrees hotter than everything else. maybe i might want a new heatsink.

[Coffee29]

tvdang7 the answer is right above your question posted by Joebuffalo on 6/19. Please read the entire thread.

[Timbosan]

Interesting thread. I cant believe intel has stated an absolute max temperature of 61.4*C for my cpu (e6300), however they have not provided anyone (developers ets) with the appropriate tools / information with which they could design a temperature monitoring program. So they have said "keep your processor under XX*C for reliable operation, but we have no way of measuring the absolute temperature. Once processors start being affected by degradation caused by overheating, what will they do? Ask the end user if they ran it out of spec! How do we know, we dont know its temperature! Intel appear to have designed a loop hole, sidestepping their responsibility to the customer. If they stated a DTS value and said keep over that for reliable operation it would be different. However even using the DTS value is dubious - it is simply a fixed number (85 or 100) at which the program tells you the cpu shuts off at - the REAL temp may be above or below that number. It is calibrated so when any given processor is at its individual and unique max temp, DTS = 0.

[unclewebb]

Intel: The TDP specification should be used to design the processor thermal solution. The TDP is not the maximum theoretical power the processor can generate.

Timbosan: That 61.4C number is the maximum recommended case temperature (Tcase) at TDP which is measured on top of the IHS at the geometric center. It's not the maximum safe temperature the processor can operate at. That's controlled solely by data from the on chip digital thermal sensors (DTS).

Intel: As an output, PROCHOT# (Processor Hot) will go active when the processor temperature monitoring sensor detects that one or both cores has reached its maximum safe operating temperature.

PROCHOT# is asserted whenl DTS=0 which Intel documents to be "the maximum safe operating temperature."

Processor shutdown or THERMTRIP# does not occur until approximately 20C after TjMax for the Desktop core processors or at a documented absolute temperature of approximately 125C for the mobile Core 2 Duo processors.

Intel: Regardless of enabling the automatic or on-demand modes, in the event of a catastrophic cooling failure, the processor will automatically shut down when the silicon has reached a temperature of approximately 125 °C. At this point the THERMTRIP# signal will go active.

The Core 2 Duo has a huge amount of temperature head room and as long as the DTS reports a positive number you are operating it within the Intel specifications and you aren't voiding your warranty by doing so.

The safe operating temperature, processor throttling and shutdown are all controlled by the DTS. It's the only temperature data you need to know.

[Timbosan]

Ok i asked intel what the maximum operating temperature of the e6300 is, as i was worried about keeping it within its specifications. This was the response:

"I understand that you are concerned about the operating temperature of the Intel(R) Core(TM) 2 Duo processor E6300.

The maximum operating temperature of the Intel(R) Core(TM) 2 Duo processor E6300 is 61.4 degrees Celsius. As long as the processor is operating under this temperature it is operating within specifications."

That implies the cpu should not exceed 61.4*C or it is "out of spec".

I then asked what software i should use to monitor the temperature with, as i would need to be able to ensure the cpu was operating within spec. This is the response:

"Regarding your first inquiry about monitoring software, thermal management and sensors are built into the motherboard; therefore, the motherboard manufacturer should be the ones providing a monitoring solution that can read the information from the processor.

Intel would only count with monitoring software that is specific to Intel(R) desktop boards and not to the Intel(R) processors; I would recommend contacting your board manufacturer for the application you need to run to be able to verify on the processor temperature and voltages.

As well, the PECI option is a feature that is particularly handled by the system chipset and BIOS meaning that Asus* (i told them i have an asus mobo) would be the ones recommending whether this option should be enabled or disabled in the BIOS"

This is a problem, as how could asus have been able to design accurate temperature monitoring software? AFAIK there is no accurate extrapolation possible of any values the thermal monitors output into absolute temperature, without a TCC (TjMax) being documented for the core 2 duo.

[unclewebb]

Timbosan: Sounds like Intel hired a summer student and put him in charge of the C2D Temperature FUD program.

The green guy you talked to has never read through the Intel data sheets. To properly measure the case temperature of a processor you have to cut a groove in the heat spreader (IHS) and run a thin thermocouple wire to the geometric center of the processor. Sounds like a lot of work for the average person to see how their C2D is running. I think I'll stick with the much simpler and fully documented DTS readings.

[Nistomax]

I'm getting multiple readings on my phase cooled e6600 as well.
Motherboard sensor said -36C so i figured okay to boot.
CoreTemp says around 4C for cores 1 and 2, as does speedfan. It is interesting, however, that speedfan reports -27C for CPU temp.
Does this mean the cpu is running at 4 or -27 or both depending on where it is measured?