Questions about temperatures

Concerning your processor temperatures; Intel's Thermal Specification - http://ark.intel.com/products/65523/Intel-Core-i7-3770K-Processor-8M-Cache-up-to-3_90-GHz - for your i7 3770K is 67C, however, the technical definition of their specification is very complicated, so I'll break it down for you.

There are 5 thermal sensors in a 4 core processor; a single Analog sensor (CPU temperature) and 4 individual Digital sensors (Core temperatures).

The temperature shown in Intel's specification, (Tcase), is measured under tightly controlled laboratory conditions at 22C Standard Ambient (intake temperature). For lab testing only, a groove is cut into the surface of the Integrated Heat Spreader (IHS) where a thermocouple is embedded at the center. The stock cooler is attached, a steady-state 100% workload is applied, (like Prime95 Small FFT's), and thermal saturation is reached within 10 minutes.

Since there is no thermocouple on any processors outside Intel's labs, a single Analog Thermal Diode is instead used to "emulate" a thermocouple. This single analog sensor is located in the center of the lower layers of the processor package and is called "CPU" temperature, which is the equivalent of "Tcase".

The analog value is converted to digital (A to D) by the Super I/O (Input / Output) chip on the motherboard, then is calibrated to look-up tables coded into BIOS. This is the temperature you see in BIOS and in software monitoring utilities such as Asus Probe, which are provided by motherboard manufacturers.

"Core" temperature, also called "Tjunction", is measured at the heat source by an individual Digital Thermal Sensor (DTS) for each Core, which are factory calibrated. Since the CPU sensor is not in relatively close proximity to the heat source, there is a 5C thermal gradient "offset" between "Core" temperature and "CPU" temperature - which is documented in this Intel White Paper - http://arxiv.org/ftp/arxiv/papers/0709/0709.1861.pdf

This means that Intel's "Tcase" specification (CPU temperature) runs 5C less than "Core" temperatures. More correctly, since there is always some temperature sensor discrepancies between Cores, "average" Core temperature is most important. So if Prime95 Small FFT's is run for 10 minutes at 22C Ambient, then the average Core temperature is 72C.

Standard Ambient = 22C
Tcase (CPU Temp) = 67C
CPU / Core Offset + 5C
Tjunction (Core Temp) = 72C
Tj Max (Shutdown Temp) = 105C

Tj Max is Intel's Thermal Specification which defines the "Core" temperature at which the processor will shutdown. Excessive heat kills electronics. Any sustained temperatures greater than 75'ish are just too hot for a 12 hour stability test or processor longevity.

Bottom line? Your Core temperatures are well within Intel's specs. You're OK up to 72C, but remember that when running Prime95 Small FFT's, if you're testing below or above 22C Standard Ambient, then you need to add or subtract the difference so that your test results are corrected to Intel's standards. This way you eliminate variables, and your results will always be consistent and repeatable.

Concerning your GPU temperature; download and install EVGA Precision X 4.1, then set up a fan curve to keep your card from exceeding 75C.

Hope this answers any questions you may have about processor temperatures.

Comp