Incorrect Temps on C2D L2 in v.0.95

[drkuli]

First of all I appreciate the idea & the work done on Core Temp. Thanks.

But I've to say, that on L2 revision Core 2 Duo chips version 0.95 of Core Temp is incorrect. I've tested it on several boards (Abit AB9, Asus P5B-E) and several L2 rev. processors (E4300, E6300), starting on nominal multiplier & Vcore minus Vdroop under load, Scythe Ninja Plus cooler in a well vented PC case. It seems to impossible to have 80 degrees Celsius in both cores and still run dual Prime torture test (Orthos) with permanent 100% load on both cores - without any error! But it goes like this in fact, constant 79-80 C for hours! It seems, that arbitrary Tjunction=100 C with all these chips is not correct. Does it mean, that temps in rev. 0.94B (Tjunction=85 C) are correct?? Any explanations & comments??

Please do something, we really need a trustful monitoring tool, board independent...

[imposter]

What does TAT, and Speed fan tell you?

[drkuli]

TAT says me nothing, because I've disabled all TM, C1E, EIST and so on in the BIOS, a lot of bells&whistles and useless services in WXP also. TAT even doesn't start on my rig, saying it can't read something (.dll or process info, I don't remember). SpeedFan 4.32 says me exactly the same what CoreTemp 0.94 beta says. Even better, says the same Vcore as CPU-Z 1.39 and the same temps, voltages and fans rpm as BIOS (through PCProbe II v. 1.04.05, it's Asus P5B-E rev.1.02G board). The same says SIW, Everest, PCWizard and so on...

[SLi_dog]

First of all I appreciate the idea & the work done on Core Temp. Thanks.

But I've to say, that on L2 revision Core 2 Duo chips version 0.95 of Core Temp is incorrect. I've tested it on several boards (Abit AB9, Asus P5B-E) and several L2 rev. processors (E4300, E6300), starting on nominal multiplier & Vcore minus Vdroop under load, Scythe Ninja Plus cooler in a well vented PC case. It seems to impossible to have 80 degrees Celsius in both cores and still run dual Prime torture test (Orthos) with permanent 100% load on both cores - without any error! But it goes like this in fact, constant 79-80 C for hours! It seems, that arbitrary Tjunction=100 C with all these chips is not correct. Does it mean, that temps in rev. 0.94B (Tjunction=85 C) are correct?? Any explanations & comments??

Please do something, we really need a trustful monitoring tool, board independent...

Why is it incorrect?

AFAIK the L2 revision C2D chips use the same Allendale core as the E4300 which most definatly should have a Tjunction value of 100C. That was one of the major reasons for releasing the latest version as people were seeing idle temps below ambient temperatures which is far harder to believe than a L2 revision running at 80C full load. I've seen Conroe cores run 80C orthos without error

If the Tjunction is 100C wouldn't that also mean that the throttle and shutdown temperature is 15C higher also? So as long as you keep it at or below 80C it's theroetically the same as a C2D Conroe hitting 65C full load.

[drkuli]

Why is it incorrect?

Because I CANNOT BURN MY FINGERTIPS, touching heatpipes in the nearby of the CPU - when CoreTemp 0.95 tells 80C, and BIOS (through PCProbe) tells even more on CPU temp sensor. Physics is not only a theory, it's practice also and this is very simple "real world" test...

AFAIK the L2 revision C2D chips use the same Allendale core as the E4300 which most definatly should have a Tjunction value of 100C.

Is it any Intel document stating it straight and clear? Nobody knows it for sure. A lot of people believe, that when E4xx ARE Allendales, E6300/6400 ARE NOT, being simple Conroes with the half of the cache disabled.

people were seeing idle temps below ambient temperatures

I do not, with E4300 (SL9TB Q644A402) and with E6300 (SL9TA Q702A120) which makes me to suspect incorrect Tjmax detection in CoreTemp, based arbitrarily on rev/step only.

which is far harder to believe than a L2 revision running at 80C full load. I've seen Conroe cores run 80C orthos without error

I agree. But I want to know IS IT SAFE to run such temps with my CPU

If the Tjunction is 100C wouldn't that also mean that the throttle and shutdown temperature is 15C higher also? So as long as you keep it at or below 80C it's theroetically the same as a C2D Conroe hitting 65C full load.

It is. So why Intel CPU specs are 61.4C TDP in both above mentioned CPUs??

[drkuli]

There is some more light here, http://forumz.tomshardware.com/hardware ... 21745.html I'm afraid, that all guessing about steppings/Tjunctions (100C or 85C) isn't necessary. I have no idea about E4300 CPU/Core temps lower than ambient, mentioned before in this thread, but I think they're simply erroneous readings, especially on i965 boards

[SLi_dog]

Deleted - duplicate post

[SLi_dog]

Is it any Intel document stating it straight and clear? Nobody knows it for sure. A lot of people believe, that when E4xx ARE Allendales, E6300/6400 ARE NOT, being simple Conroes with the half of the cache disabled.

I'm talking about the L2 revision of the Core2Duo. The new L2 E6300 and E6400 are Allendale core Core2Duo CPUs and have a native 2mb L2 cache. These are different to the Non L2 E6300 and E6400 which used Conroe core with half of their L2 cache disabled.

I agree. But I want to know IS IT SAFE to run such temps with my CPU

That's the million dollar question and I suppose the only real way to know is to leave the Thermal Throttling enabled and run it at full load with Orthos or TAT and see what temperature it throttles at, then you'll know where your maximum temperature limit is.


I don't know the answers to the rest of your questions but from what I've seen I'm more inclined to believe that the L2 revision E6300/E6400 and E4300/E4400 CPUs that use the Allendale core run hotter than the conroe and so using the same temperature readout isn't right, but as you ask what is?

There is some more light here, http://forumz.tomshardware.com/hardware ... 21745.html I'm afraid, that all guessing about steppings/Tjunctions (100C or 85C) isn't necessary. I have no idea about E4300 CPU/Core temps lower than ambient, mentioned before in this thread, but I think they're simply erroneous readings, especially on i965 boards

I've read numerous guides on core temperature reading software and most of them are rather confusing.

BTW, there are too many E4300s reading below ambient temperatures on v0.94 for it to be an "error". In fact I think that exact reason was a very big part of the need for the new 0.95 version .

[drkuli]

From http://forumz.tomshardware.com/hardware ... 21745.html

(E) Any hardware and / or software may misreport Tcase and / or Tjunction temps.

(F) 965 chipsets may misreport Tcase and Tjunction temperatures with +/-15c offsets.

and

(I) C2D’s manufactured with concave Integrated Heat Spreaders may report high Deltas and temps.

(J) An improperly seated CPU cooler is the leading cause of abnormally high temperatures.

I'm ready to disassemble my mobo&CPU to check that concave, which I'm suspecting. I have all symptoms of it and checking this is really simple - some thermal grease on IHS and a piece of glass. That's the last thing I can do. Thanks for your help. I'll keep posting.

[fgw]

drkuli,

http://forumz.tomshardware.com/hardware ... 21745.html

i would not rely too much on this post over at the thg forums. there are a lot of misinterpretations in it!
lets start with the things you can confirm by looking at intel datasheets:

Datasheet
http://www.intel.com/design/processor/d ... 313278.htm

Thermal and Mechanical Design Guidelines
http://www.intel.com/design/processor/d ... 313685.htm

yes, there are more than one sensors measuring temperatures

• one thermal diode located on the processor die
• two digital temperature sensors within each core on c2d
• four digital temperature sensors within each core on quad

intel defines tcase at the temperature measured on top of the ihs and at the center of the ihs.

afik, bios or software is not displaying tcase! the temperature displayed there is simply the processor temperature measured via the thermal diode. the thermal diode as implemented by intel is delivering a voltage proportional to processor temperature. the software using this signal has to calibrate this readings and convert it to a temperature. as different software, or bios, is calibrating this readings differently, you get different temperatures but by no way tcase as described above.

the digital temperature sensors on the other hand, are located directly within the cores near the hottest places. this sensor has a smaller footprint and thus can be located easier within the core. the reading, as opposed to the thermal diode, is not a voltage! digital temperature sensors convert the temperature directly into a binary value (dts reading) and store it in a register within the processor thus eliminating the need of calibrating this sensor readings.

the problem here is, this dts reading is not absolute. its a relative temperature to the thermal control circuit activation temperature (prochot#). as this thermal control circuit activation temperature is calibrated during manufacturing on a per part basis and is not read by software it is impossible to convert dts readings into an absolute temperature.

on mobile processors tjunction as a reference temperature instead of thermal control circuit activation temperature. also, there were just two possible tjunction values used on mobile processors in the past (don't know intel plans on future mobile processors). on this mobile processors, there is a bit in a register which can be read to check if tjunction is at 85c or if it is at 100c! absolute temperature can now simply calculated by substracting dts reading from tjunction. thats how coretemp, and i assume all other programs using digital temperature sensors readings, calculate absolute temperatures.

using this method on desktop or server processors might result in a temperature reading that look right, but this does not mean it is correct.
there is only one correct temperature reading on intel core technology processors: relative temperature (dts reading) as introduced incoretemp 0.95

everything else, besides mobile processors as discussed above, is speculation!

and so is most of the following:

• Tcase + 15c = Tjunction its more like: dts reading + 15c = thermal control cicuit activation temperature
• Thermal Case Temperatures of 60c is hot, 55c is warm, and 50c is safe. well, this might be true, but there is no way to measure tcase besides a temp probe on the ihs! do you use one? i don't.
• The difference between Tcase (BIOS, Motherboard Utilities and SpeedFan: CPU or Temp X) and Tjunction (TAT and SpeedFan: Core 0 / Core 1) is Tcase + 15c = Tjunction
• Vcore should not exceed ~ 1.5v.
• Tjunction is always ~ 15c higher than Tcase.
• Tcase is always higher than Ambient. as any temp as long as you are on air or water ...
• Tcase Idle should be ~ 1 to 15c higher than Ambient.
• Tjunction Idle should be ~ 15 to 30c higher than Ambient.
• Tcase Load should not exceed ~ 55c with TAT @ 100% Load. again, how is it measured?
• Tjunction Load should not exceed ~ 70c with TAT @ 100% Load.
• Idle to Load Delta should not exceed ~ 25c.
• Tjunction Results are Hottest Core Idle and Load.
• Vcore will typically sag ~ .025 volts under Load. depends on motherboard
• Any hardware and / or software may misreport Tcase and / or Tjunction temps.
• 965 chipsets may misreport Tcase and Tjunction temperatures with +/-15c offsets. the chipset is not involved at all - all sensors are within the cpu. well, calibration of thermal diode is done in bios
• If TAT will not run, then Orthos Priority 9 Small FFT’s simulates 88% of TAT ~ 5c lower.
• C2D’s manufactured with concave Integrated Heat Spreaders may report high Deltas and temps. true
• An improperly seated CPU cooler is the leading cause of abnormally high temperatures. also true, but again - no surprise here

added comments to some of them although almost all are either questionable or obvious...

[drkuli]

Thank you for your post. But I can't agree.

i would not rely too much on this post over at the thg forums. there are a lot of misinterpretations in it!

Well, tens of thousands of users cannot be ALL wrong... And this is not the site for tech noobs, so most of them have enough knowledge to test these behaviors, in real world, not in theory. Most of them have read Intel's documents, quoted by you, more than once.

as this thermal control circuit activation temperature is calibrated during manufacturing on a per part basis and is not read by software it is impossible to convert dts readings into an absolute temperature

This is what I've already said.

there is only one correct temperature reading on intel core technology processors: relative temperature (dts reading) as introduced incoretemp 0.95
everything else, besides mobile processors as discussed above, is speculation!

If you mean 0.95 configured to show delta instead of absolute - I agree.

and so is most of the following...
...added comments to some of them although almost all are either questionable or obvious...

Well, this is neither a Holy Bible, nor Newton's Law - only some notes taken from PRACTICE, not theory. I don't know anything of your OC experiences, but mine are as long as I can remeber. My first OCed CPU was i486 33MHz@50MHz (a remarkable 51% OC ) in the very early 90's. I really doubt if I had ANY non-OCed CPU at all. I wouldn't call any precise set of notes from practical experience of OCing "questionable or obvious" since they're repeatable, i.e. can be reproduced on demand.

I might be wrong and my conclusion too early, but setting TjunctionMAX arbitralily at 100C because of L2 core stepping only - since TjMAX is INVISIBLE BY SOFTWARE, Intel says - is an error, as practice prove it.

And WHAT WITH MY FINGERTIPS? After 15 minutes of load I've measured the temp on the edge of copper plate (under the heatpipe, plate has direct contact with IHS) at the bottom of CPU cooler. It was done with digital thermometer, which is officially approved as +/- 0.5C error max. The temp measured was 34.4C. I've touched the heatpipes near the plate with my fingertips - heatpipes were cold! And CoreTemp 0.95 was showing 80C! BIOS (through Asus utility) was showing CPU (through thermal diode or DTS between two cores, I dont care...) at 78! Could anybody explain me this simple physics (thermodynamics exactly)??? I personally don't believe in such physical phenomena (should I say miracles?) as 40C temps differences inside solid copper plate at the bottom of Sythe Ninja Plus cooler!!! And this is PRACTICE as I understand it.

And NO, my IHS is not concave, as I checked it against 4mm glass.

EDIT:
http://www.alcpu.com/forums/viewtopic.php?t=231

the cpu detection end of the coretemp problem is being worked on

if it is reading the clock speed wrong, what makes the temp reading right and not wrong also?

Yes, I'm aware of the problem.
Its a limitation of an old frequency detection algorithm.
A fixed is planned in a future release.

This should end our discussion here, since the author of CoreTemp, Arthur Liberman, was quoted in the last.