Real Temp - New temp program for Intel Core processors

[CompuTronix]

Originally Posted by Lunadesign
Regarding the CPU temp that's reading 20C (Tcase), I thought this sensor was located on the case of the processor but read by the motherboard?

I'll have to check up on this. I thought it was reading a sensor that was located in the CPU socket but don't quote me on that.

Unclewebb & lunadesign,

This is a very common misunderstanding, and is precisely why users hesitate to trust Intel's Tcase sensor, which is the processor-specific thermal specification shown in Intel's Processor Spec Finder - http://processorfinder.intel.com/det...px?sSpec=SLAWQ

The era of the thermocouple-in-the-center-of-the-CPU-socket has long since passed.

The following Intel document - http://arxiv.org/ftp/arxiv/papers/0709/0709.1861.pdf - clearly shows on Page 2, Figure 1, upper right hand corner, the "Analog Sensor" which is embedded within the substrate layers of the processor package. Excerpts from my Core 2 Quad and Duo Temperature Guide - http://www.tomshardware.com/forum/22...perature-guide - explain how this Tcase sensor has worked for the past several years, which actually applies to some previous generations of Intel, as well as AMD processors:


"Section 1: Introduction

Core 2 Quad and Duo processors have 2 different types of temperature sensors; a CPU Case (not computer case) Thermal Diode located within the CPU die between the Cores, and Digital Thermal Sensors located within each Core...

Section 3: Interpretation

The first part of the spec refers to a measuring point on the Integrated Heat Spreader (IHS). Since a thermocouple is embedded in the IHS for lab tests only, IHS temperature is replicated using a CPU Case Thermal Diode integrated between the Cores. Maximum Case Temperature is determined by Spec#. The CPU Case Thermal Diode is how Tcase is measured, and is the CPU temperature displayed in BIOS and the software utility SpeedFan...

Section 5: Findings

(A) Tcase is acquired on the CPU Die from the CPU Case Thermal Diode as an analog level, which is converted to a digital value by the super I/O chip on the motherboard. The digital value is BIOS Calibrated and displayed by temperature software. BIOS Calibrations affect the accuracy of Tcase, or CPU temperature.

(B) Tjunction is acquired within the Cores from Thermal Diodes as analog levels, which are converted to digital values by the Digital Thermal Sensors (DTS) within each Core. The digital values are Factory Calibrated and displayed by temperature software. Factory Calibrations affect the accuracy of Tjunction, or Core temperatures.

(C) Tcase and Tjunction are both acquired from Thermal Diodes. Tcase and Tjunction analog to digital (A to D) conversions are executed by separate devices in different locations. BIOS Calibrations from motherboard manufacturers, Factory Calibrations from Intel, and popular temperature utilities are frequently inaccurate.

(D) Intel shows Maximum Case Temperature (Tcase Max) in the Processor Spec Finder, which is the only temperature that Intel supports on Core 2 desktop processors. Ambient to Tcase Delta has known Offsets which vary with power dissipation and cooler efficiency, and can be Calibrated at Idle using a standardized Test Setup..."


Since the first release of Core Temp, the overclocking community has become so brainwashed on core temperatures, that they now overlook CPU temperature as a reliable thermal measurement, let alone as a secondary reference. I have yet to see a Tcase sensor "stick", and as Intel has designed this sensor specifically for temperature measurements and depends on it's accuracy, my experience and observations is that the Tcase sensor scales with linear characteristics.

The only problem with the Tcase sensor is that BIOS programmers are confined to "canned" values, and sometimes incorrectly code just one of the many Socket 775 variants into BIOS. Regardless of whether BIOS is correctly offset for a particular processor, Tcase can still be calibrated in SpeedFan to an accuracy of within a degree or two. By using a similar standardized test setup for low Vcore and frequency, with covers removed and fans at 100% RPM, if ambient is accurately measured, then idle power dissipation and CPU cooler thermal efficiency are easily calculated to provide accurate CPU temperature.

I Hope this helps to clear things up.

Comp