- Joined
- May 2, 2007
I found this argument in a (very long) thread on the HardForum.
http://www.hardforum.com/showthread.php?t=1174781
Here's how this programmer guy Unclewebb puts it:
CoreTemp 0.95 is definitely right for the original E6x00 Conroe based processors. It is also correct in reporting the new Allandale E4300 processor. The E4300 has a Tjunction of 100C which means it won't start throttling until it hits ~97C.
The earlier Conroe processors have a Tjunction of 85C.
Most of the core processors used in laptops all have an Intel documented Tjunction of 100C so it shouldn't be too surprising that the E4300 Allendale also has a Tjunction of 100C.
The formula used is:
CoreTemp = Tjunction - DTS
DTS is the reading from the digital thermal sensor within the Intel C2D. Your processor reaches its maximum temperature when the DTS signal approaches zero. If Tjunction for the Allendales is really 85C then the reported temperature would be 15C less. The problem with this is that at idle you can end up with a reported temperature below ambient with air cooling which is impossible. This proves that it can't be 85C and must be 100C.
In the bios lock your computer at 266 x 6 or 200 x 6 for the E4300 and drop your core voltage down to 1.175 to 1.200 volts. If your idle temperature is below your ambient temperature then your monitoring software is wrong.
CoreTemp 0.95 passes this test. CoreTemp 0.94 does not pass this test on the E4300 which is why he corrected it in the most recent release.
The problem is that Tjunction or TjMax is not properly documented by Intel so individual software developers can not write temperature monitoring programs that are 100% accurate across their entire line of processors. It's a guessing game and the only company to blame is Intel.
The calculation is simple:
core temperature = Tjunction - DTS
Intel documents how to read the digital thermal sensor ( DTS ) value but does not document how to read the Tjunction value which is needed. Without knowing the correct Tjunction it is impossible to calculate an absolute core temperature value. One person from Intel implied that there is no way to read Tjunction from a processor which may or may not be true.
An assumed Tjunction of 85C for the E4300 results in idle temps below ambient which is impossible so it is assumed to be 100C.
Unfortunately the developer of CoreTemp also assumed that the new E6300 / E6400 cpus built on the same Allendale core must also have a Tjunction of 100C but TheRapture proved that to be wrong in his above post.
Here's what seems to be true:
Tjunction:
E4300 = 100C
All other presently available Core 2 desktop processors have a Tjunction of 85C. This includes the original revision B2 Conroe based processors as well as the E6300 / E6400 revision L2 processors.
Laptop processors have a Tjunction of 100C. This includes all Core Solo, Cord Duo and Core 2 Duo mobile processors:
T1300, T1400, T2300 to T2700, T5500, T5600, T7200, T7400, T7600
CoreTemp 0.95 works properly on all processors except the revision L2 E6300 / E6400.
If you have a revision L2 E6300 / E6400 then use CoreTemp 0.94.
http://www.hardforum.com/showthread.php?t=1174781
Here's how this programmer guy Unclewebb puts it:
CoreTemp 0.95 is definitely right for the original E6x00 Conroe based processors. It is also correct in reporting the new Allandale E4300 processor. The E4300 has a Tjunction of 100C which means it won't start throttling until it hits ~97C.
The earlier Conroe processors have a Tjunction of 85C.
Most of the core processors used in laptops all have an Intel documented Tjunction of 100C so it shouldn't be too surprising that the E4300 Allendale also has a Tjunction of 100C.
The formula used is:
CoreTemp = Tjunction - DTS
DTS is the reading from the digital thermal sensor within the Intel C2D. Your processor reaches its maximum temperature when the DTS signal approaches zero. If Tjunction for the Allendales is really 85C then the reported temperature would be 15C less. The problem with this is that at idle you can end up with a reported temperature below ambient with air cooling which is impossible. This proves that it can't be 85C and must be 100C.
In the bios lock your computer at 266 x 6 or 200 x 6 for the E4300 and drop your core voltage down to 1.175 to 1.200 volts. If your idle temperature is below your ambient temperature then your monitoring software is wrong.
CoreTemp 0.95 passes this test. CoreTemp 0.94 does not pass this test on the E4300 which is why he corrected it in the most recent release.
The problem is that Tjunction or TjMax is not properly documented by Intel so individual software developers can not write temperature monitoring programs that are 100% accurate across their entire line of processors. It's a guessing game and the only company to blame is Intel.
The calculation is simple:
core temperature = Tjunction - DTS
Intel documents how to read the digital thermal sensor ( DTS ) value but does not document how to read the Tjunction value which is needed. Without knowing the correct Tjunction it is impossible to calculate an absolute core temperature value. One person from Intel implied that there is no way to read Tjunction from a processor which may or may not be true.
An assumed Tjunction of 85C for the E4300 results in idle temps below ambient which is impossible so it is assumed to be 100C.
Unfortunately the developer of CoreTemp also assumed that the new E6300 / E6400 cpus built on the same Allendale core must also have a Tjunction of 100C but TheRapture proved that to be wrong in his above post.
Here's what seems to be true:
Tjunction:
E4300 = 100C
All other presently available Core 2 desktop processors have a Tjunction of 85C. This includes the original revision B2 Conroe based processors as well as the E6300 / E6400 revision L2 processors.
Laptop processors have a Tjunction of 100C. This includes all Core Solo, Cord Duo and Core 2 Duo mobile processors:
T1300, T1400, T2300 to T2700, T5500, T5600, T7200, T7400, T7600
CoreTemp 0.95 works properly on all processors except the revision L2 E6300 / E6400.
If you have a revision L2 E6300 / E6400 then use CoreTemp 0.94.
