From the
Intel Temperature Guide -
http://www.tomshardware.com/forum/id-1808604/intel-temperature-guide.html
" ...
Section 10 - Software Tools
In order to properly test and evaluate your temperatures whether overclocked or not, you'll need to download the following freeware utilities:
CoreTemp - http://www.alcpu.com/CoreTemp/
CPU-Z -
http://www.cpuid.com/softwares/cpu-z.html
Prime95 v26.6 -
http://windows-downloads-center.blogspot.com/2011/04/prime95-266.html
Real Temp - http://www.techpowerup.com/downloads/2089/real-temp-3-70/
SpeedFan -
http://www.almico.com/sfdownload.php
Section 11 - Thermal Testing @ 100% Workload
We all remember science class where one of the basic principals for conducting any scientifically controlled experiment, is that it's critical to follow the same procedure every time. This eliminated variables so results will be consistent and repeatable. If everyone is testing their rigs with X stress software at Y Ambient temperature with Z measuring software, then it's impossible to compare apples to apples.
This is why processor temperatures continue to be a major source of confusion and debate. In this Section we'll explain how to properly test your rig. It's important to remember that
we are not stress testing; we are thermal testing to produce a Core temperature benchmark.
Prime95 Small FFT's is the standard for CPU thermal testing, because it's a steady-state 100% workload. This is the test that Real Temp uses to test sensor movement. The link above is to version 26.6, which is well suited to all Core 2 and Core i variants.
Core i 2nd, 3rd and 4th Generation CPU's have AVX (Advanced Vector Extension) instruction sets. Recent versions of Prime95 run AVX code on the Floating Point Unit (FPU) math coprocessor, which produces unrealistically extreme temperatures. The FPU test in the software utility AIDA64 shows the same results.
It's not necessary to run AVX code for thermal testing. Prime95 v26.6 produces temperatures on 3rd and 4th Generation processors more consistent with 2nd Generation, which also have AVX instructions, but do not suffer from thermal extremes due to having a soldered Integrated Heat Spreader and a 35% larger Die.
Prime95's default test, Blend, is a cyclic workload for testing memory stability, and Large FFT's combines CPU and memory tests. As such, Blend and Large FFT's both have cyclic workloads which are unsuitable for CPU thermal testing.
Other stability tests such as Linpack and Intel Burn Test have cycles that load all registers with all one's, which is equivalent to a 110% workload, and are also unsuitable for CPU thermal testing. The software utility OCCT runs elements of Linpack and Prime95.
Shown above from left to right: Small FFT's, Blend, Linpack and Intel Burn Test.
Shown above from left to right: Small FFT's, Intel Extreme Tuning Utility CPU Test, and AIDA64 CPU Test.
The "Charts" in SpeedFan show how these tests create different thermal signatures. Intel Extreme Tuning Utility is also a cyclic workload. Although AIDA64's CPU test is steady-state, the workload is insufficient, and it's not available as freeware.
Setup:
Testing should be performed with your computer clear of desk enclosures or items that block airflow. Covers should be removed and all fans and circulating pump (if equipped with liquid cooling) at 100% RPM, so temperatures can be tested under ideal conditions.
Testing close to 22C Ambient is preferred so as to provide normal thermal headroom, but is not required. Testing at high Ambient temperatures should be avoided. If adequate A/C is unavailable, then test late at night or early in the morning when Ambient is lowest.
When performing a thermal test above 22C Ambient, remember to subtract the difference so that test results are corrected to Standard Ambient. This eliminates variables so results will be consistent and repeatable.
Example:
During Thermal Testing @ 100% Workload;
if
measured Ambient is 25C, and
reported Core temperature is 80C,
then at
standard Ambient 22C,
corrected Core temperature would be 77C.
Test:
Run Prime95 v26.6 Small FFT's for 10 minutes, then use your thermometer to measure Ambient. Use Core Temp or Real Temp to measure your Core temperatures. Correct your results to Standard Ambient.
Results:
Core temperatures
should be in the mid 70's for most processor variants. However, depending on variables such as clock speed, Vcore, Ambient and cooling, Core i 3rd Generation, and especially 4th Generation temperatures could rise above 90C. Core temperatures in the
mid 70's are safe during real-world everyday workloads.
Exception: Early Core 2 1st Generation processors with stepping revisions B2 and B3 and have lower Tcase and TjMax specifications than other variants. Core temperatures on these processors should be kept under 70C.
Deviations in sensor accuracy between individual Cores can be up to +/- 5C. This means there could be 10C between the highest and lowest Cores, so "average" Core temperature is often more realistic. ... "
CT