when monitoring CPU temps for quad core processors, is it important to know how hot each individual core is getting?
im runining Everest Ultimate to monitor and my temps are
CPU - 28 C
CPU1 - 40 C
CPU2 - 40 C
CPU3 - 52 C
CPU4 - 52 C
Why so many different temperatures? Im water cooling my intel 9450 quad core processor and shouldn't all the temps be roughly the same?
45 nanometer processors are known to have faulty DTS (Core temperature) sensors, which "stick" at Idle, and won't indicate the actual Idle temperatures of the Cores. Use Real Temp 2.6 - http://www.techpowerup.com/realtemp/ - "Test Sensors" button to test your processor Cores to determine the health of your Q9450 Core sensors.
Also, don't use Everest, or the ever popular "Core Temp", which indicates 10c too hot. Real Temp is the only Core temperature monitoring utility which is accurate. The Real Temp documentation - http://www.techpowerup.com/realtemp/docs.php - explains what this utility does differently than the other popular utilites, and why it's more accurate.
As has been stated, CPU is CPU temperature, and CPU 1 thru 4 are Core temperatures. For an explanation of what the difference is between CPU temperature and Core temperatures, please refer to my Core 2 Quad and Duo Temperature Guide - http://www.tomshardware.com/forum/221745-29-core-quad-t...
The Guide can be used with SpeedFan 4.34 to achieve accurately calibrated CPU temperature AND Core temperatures.
CPU is a socket temp sensor
Just so everyone is clear on this point, this is a very common misconception, 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/details.aspx?sSpec=SLA...
The era of the thermocouple-in-the-center-of-the-CPU-socket has long since passed.
Excerpts from my Temperature 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 single 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 monitoring 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 (Input/Output) chip on the motherboard. The digital value is BIOS Calibrated and displayed by temperature software. BIOS Calibration affects 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 Calibration affects 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 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 factors are used to provide accurate CPU temperature.
Yeah, CPU temperature accuracy (Tcase) depends upon whether or not BIOS programmers have accurate tables, and whether they makes mistakes during coding. Regardless, CPU temperature can still be dialed in tight by using the Guide.