TCase higher than TJunction. Why? (CompuTronix?)

Here is a screen of my new PC. It clearly shows, through various tools, that the CPU Tcase temp is higher than the 2 core temps by 13C. How does this make sense? Did I connect something on the MB wrong? What should I trust?

At Idle;

Core 0,1 are 29C (Speedfan, TAT, CoreTemp)
CPU is 41C (Asus Probe, Speedfan)

Brendan
--------------------------------------
e6600 @3000 mhz/stock heatsink
Asus P5B-e/latest bios 1202
Corsair XMS2 6400c4/2gb
74 Gb raptor
320 Gb Seagate
Radeon X1950 Pro

You have the temps backwards. The individual core readings are Tcase and the single CPU temp is tjunction.

That is how it is supposed to look.

In your screen shot core 0 = tcase and CPU = tjunction [speedfan]

Ok there seems some inherent contradictions in the temp guide, things that did not exist when I originaly read it.

So tcase = 41c and tjunction = 29c according to CompuTronix and based on the following, right?

However, I have never seen a screenshot of SpeedFan with Core 0/1 > CPU which is weird. My system with Speedfan is the same as yours, Core 0/1 < CPU.

Based on your screenshot your temps are fine.

SuperFly03, there are no contradictions in the Guide, but there are many examples on this Forum of SpeedFan screenshots which correctly show Tjunction values (Core 0 / Core 1) higher than Tcase (CPU or Temp X). Your advice to bh626pro is unsound:

Respectfully, please re-read the Guide with emphasis on comprehension. There's alot of information to take in, so only a few users "get it" the first time. Many need to read it several times, and unfortunately, there are some who will never "get it".

The Guide is not a document which I take lightly. Every concept, every paragraph, every sentence, every word, and every punctuation has been painstakingly thought out. I can't begin to estimate how many hundreds of hours of research and effort went into it, as well as the updates and edits, and how many thousands of users it's helped. If the Guide were invalid or contadictory, it would never have become a THG Forum "Sticky".

Hope this helps,

Comp 8)

Computronix, here are the info fields you requested, below in red. I still don't get it - why is TCase > Core?

My concern is that my Mobo is defective somehow. Is there a BIOS setting that would affect the temperature readings?

Setup

Asus P5B-E
1202 BIOS
Vcore = Manual
C1E / EIST = Disabled
CPU Fan = Manual, 100%
Computer Case Fans = Manual 100%
Computer Case Covers = Installed
Primary Test = TAT @ 100% 10 Minutes

Brendan's Results

Tcase (SpeedFan CPU and Asus Probe CPU) = 41c Idle, 56c Load
Tjunction (TAT and SpeedFan: Core0/Core1) Hottest Core = 30c Idle, 44c Load

My BIOS reads around 42C for the "CPU Temperature", so it would seem that the Tcase (SpeedFan CPU and Asus Probe CPU temps) are correct. So the question remains; is there any logical reason that the TJunction core temps are lower than the TCase? {EDIT} Yes! if PECI is disabled - see below.

Variables

Ambient = 22c
Chipset = 965P
C2D = E6600
CPU Cooler= Stock Intel
Frequency = 3.0 Ghz
Load = TAT @ 100% 10 minutes
Motherboard = Asus P5B-E
Vcore = 1.42

The temp readings depend on how the BIOS is setup in the Asus P5B mobo. I read through most of this 141 page thermal design doc from Intel found at http://www.intel.com/design/proces [...] 13685.htm.

Interesting points from the doc;

Digital Thermal Sensor
The Intel Core™2 Duo desktop processor E6000/E4000 sequence introduces the Digital Thermal Sensor (DTS) as the on-die sensor to use for fan speed control (FSC). The DTS can be accessed by two methods. The first is via a MSR (model specific register). The value read via the MSR is an unsigned number of degrees C away from TCC activation (Tjunction in CoreTemp). The second method which is expected to be the primary method for FSC is via the PECI interface. The value of the DTS when read via the PECI interface is always negative and again is degrees C away from TCC activation (Delta to TJunction).

PECI - Platform Environmental Control Interface
The PECI interface is a proprietary single wire bus between the processor and the chipset or other health monitoring device. At this time the digital thermal sensor is the only data being transmitted. Core 2 Duo processor E6000 and E4000 sequences do not have an on-die thermal diode.

Design Specs
Intel states that damage to the processor is likely if the temperature exceeds 68C or 155F, which can be avoided by using Thermal Management. In fact the doc states "To maintain compatibility with previous generations of processors, which have no integrated thermal logic, the Thermal Control Circuit portion of Thermal Monitor is disabled by default. During the boot process, the BIOS must enable the Thermal Control Circuit. Thermal Monitor must be enabled to ensure proper processor operation. "

What To Do?
In the BIOS;
> enable TM Management
> enable PECI - this seems to put the temps right. TCase is now lower than Core.

My Results at Idle
PECI disabled - [BIOS; CPU 33C, MB 41C]. CoreTemp 32C. CPU* 45C
PECI enabled - [BIOS; CPU 45C, MB 41C]. CoreTemp 32C. CPU* 24C

* The CPU read 24C in Asus Probe, SpeedFan, and AI Suite. Ambient temp was 18-20C

At load with PECI on, Core was 59C, CPU was 49C

Anybody know what the eVGA equivalent is for PECI? I looked around and didn't see it in my BIOS.

unless their rediculassly high, dont worry

But that wouldn't change the temps that are reported from TAT. And from what I understand, those are the actual temps which are taken from diodes inside the cores...

This justification, the holy C2D temperature Guide:

it doesnt say "Tjunction should be ~15c higher then Tcase" it says "Tjunction is ALWAYS ~15c higher then Tcase". So I dont see what all the fuss is about. The actual offset probly lies somewhere inbetween 12-18c so I dont see why 15c offset is the end of the world.

T-junction although it is a term used in the mobile platform is actually the point at where TCC activation occurs (somewhere around 85C).
The core temps are read through the PECI and are in negative numbers away from TCC activation
85C minus 56 or -56C = 29C(core temp)
This reading of 29C is most likely in error from either the bios revision out of date or PECI has been disabled in bios.
Some motherboard manufactures are slower to update the bios than others and that’s why we see a few temps out of line.

on the Asus motherboard its in the cpu section of the bios.
I dont own the EVGA so I cant help there

Does it actually say PECI?

bh626pro, as kwalker has pointed out, we, the end user, are all too often the unknowing purchasers of hardware / firmware / software which has been released prematurely, with deficiencies. In this instance, users are once again being burned by the BIOS bug. From the Guide:

PECI support is only available on some newer motherboards, but as you have shown, there are BIOS discrepancies. I have noted that some users have reported inverted Tcase and Tjunction temps with PECI enabled, so again, there are inconsistencies which don't support any hard and fast rules.

In my next update to the Guide, I will be introducing a simple calibration technique that I've been developing, which should provide reasonably accurate Tcase and Tjunction temperature offsets accross nearly all C2D hardware / software platforms. I will also be including some content regarding PECI, so that users don't continue to be derailed by this inverted temp / BIOS issue.

Regarding your temperatures, if we plug in the new Ambient and Tcase values, we can see that temps are closer, but still don't quite measure up:

Results

Tcase (SpeedFan CPU) = 24c Idle, 49c Load
Tjunction (SpeedFan: Core0/Core1) = 32c Idle, 59c Load

Variables

Ambient = 18 - 20c
Chipset = 965P
C2D = E6600
CPU Cooler= Stock Intel
Frequency = 3.0 Ghz
Load = TAT @ 100% 10 minutes
Motherboard = Asus P5B-E
Vcore = 1.42

Although Tcase Idle is reasonable, Tcase Load is questionable. The Intel boxed cooler typically can barely hold it's own at 1.35 Vcore in a well ventilated case, so I think Tcase is showing some non-linearity at upper scale, but is probably an insignificant value. However, Tjunction Idle and Load are clearly inaccurate relative to Ambient, Vcore, Stock cooler, and Tcase to Tjunction Delta.

My recommendation is that you enter a +5 Offset in SpeedFan for both Cores, click on "Show in Tray" Core 0, and drink some beer.

Hope this helps,

Comp 8)

Hey nice work on sorting out the problem CompuTronix

its an awesome feeling when you can identify a problem, do one google search, find a thread that exactly describes your problem and fix it with one button push.

After enabling the option on my p5b-deluxe my Tjunctions jumped up a degree (load and idle) but my Tcase dropped by 15 or 16 degrees to around where I would expect it to be.

E6420 1.475v (bios)
cpuZ vCore (Idle 1.44 vs Load 1.408)
FSB450 x7
Noctua UF-12 cooler
Idle Tjunction 35, Tcase 21
Load Tjunction 59, Tcase49

Thanks guys!