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Intel Temperature Guide

Intel Temperature Guide - by CompuTronix

Update: 12 March 2017


Preface

The topic of processor temperatures can be quite confusing. The purpose of this Guide is to provide an understanding of standards, specifications, thermal relationships and test methods so that temperatures can be uniformly tested and compared. This Guide supports Core i and Core 2 desktop processors running Windows Operating Systems.


Sections

1 - Introduction
2 - Ambient Temperature
3 - CPU Temperature
4 - Package Temperature
5 - Core Temperature
6 - Throttle Temperature
7 - Relative Temperatures
8 - Power and Temperature
9 - Overclocking and Voltage
10 - The TIM Problem
11 - Thermal Testing Tools
12 - Thermal Testing Basics
13 - Thermal Testing @ 100% Workload
14 - Thermal Testing @ Idle
15 - Improving Temperatures
16 - Summary
17 - References


Section 1 - Introduction

Intel desktop processors have temperatures for each "Core", plus a temperature for the entire "CPU", so Quad Cores have five temperatures. Core temperatures are measured at the heat sources near the transistor "junctions" inside each of the Cores. CPU temperature is instead a single external measurement centered on the surface of the CPU's "Case" or "Integrated Heat Spreader" where the cooler is seated.

CPU temperature is a factory only measurement used for Intel's "Tcase" Thermal Specification, so Tcase is CPU temperature, not Core temperature. If users look up their processor's Thermal Specification at Intel's Product Information website, they often don't read or understand the definition. Since there are many software utilities for monitoring Core temperature, users often confuse Tcase with Core temperature.

Core temperature (Tjunction) is 5C higher than CPU temperature (Tcase) due to differences in the proximity of sensors to heat sources. The relationship between these temperatures is not readily documented for the average user, so the terms are frequently misconstrued. In order to get a clear perspective of processor temperatures, it's important to familiarize yourself with the terminology and specifications.

Note: For 7th Generation, the Thermal Specification "Tcase" has been replaced with "Tjuction".

Here’s a list of processors referenced according to microarchitecture:

7th Generation Core i, 14 nanometer
6th Generation Core i, 14 nanometer
5th Generation Core i, 14 nanometer
4th Generation Core i, 22 nanometer
3rd Generation Core i, 22 nanometer
2nd Generation Core i, 32 nanometer
Previous (1st) Generation Core i, 32 nanometer
Previous (1st) Generation Core i, 45 nanometer
Legacy Core 2, 45 nanometer
Legacy Core 2, 65 nanometer

Use CPU-Z to identify your processor, then look up the specifications at Intel Product Information:

• CPU-Z - http://www.cpuid.com/softwares/cpu-z.html
• Intel Product Information - http://ark.intel.com


Section 2 - Ambient Temperature

Also called "room" temperature, this is the temperature measured at your computer's air intake. Standard Ambient temperature is 22C or 72F, which is normal room temperature. Ambient temperature is a reference value for Intel’s Thermal Specifications. Knowing your Ambient temperature is important because Ambient directly affects all computer temperatures. Use a trusted analog, digital or IR thermometer to measure Ambient temperature.

Here's the temperature conversions and a short scale:

Cx9/5+32=F ... or ... F-32/9x5=C ... or a change of 1C = a change of 1.8F

30.0C = 86.0F Hot
29.0C = 84.2F
28.0C = 82.4F
27.0C = 80.6F
26.0C = 78.8F Warm
25.0C = 77.0F
24.0C = 75.2F
23.0C = 73.4F
22.0C = 71.6F Norm ... or ... 22.2C = 72.0F
21.0C = 69.8F
20.0C = 68.0F
19.0C = 66.2F
18.0C = 64.4F Cool

When you power up your rig from a cold start, all components are at Ambient, so temperatures can only go up. With conventional air or liquid cooling, no temperatures can be less than or equal to Ambient.

As Ambient temperature increases, thermal headroom and overclocking potential decreases.


Section 3 - CPU Temperature

Also called "Tcase", this is the temperature shown in Intel's Thermal Specification (does not apply to 7th Generation). It's measured on the surface of the Integrated Heat Spreader (IHS) under carefully controlled conditions. For lab testing only, a groove is cut into the surface of the IHS where a "thermocouple" is embedded at the center, which accurately measures the temperature of the entire CPU. The stock cooler is then seated and the processor is tested at a steady 100% workload. One of two different methods are used to display “CPU” temperature in BIOS and in monitoring utilities.

Method 1: Legacy Core 2 Socket 775 and Previous (1st) Generation Core i Socket 1366 use a single Analog Thermal Diode centered under the Cores to substitute for a laboratory thermocouple. The Analog value is converted to Digital (A to D) by the motherboard's Super I/O (Input / Output) chip, then is calibrated to look-up tables coded into BIOS. For these processors, the monitoring utility provided by your motherboard manufacturer on the Driver DVD displays “CPU” temperature in Windows. Accuracy can vary greatly with BIOS updates, so "CPU" temperature can be grossly inaccurate.

Method 2: Processors for Sockets 115x and Socket 2011 no longer use an Analog Thermal Diode, but instead substitute the "hottest Core" for "CPU" temperature, which is a contradiction in terms that confuses users. This is the temperature shown in BIOS, and on some recent motherboards is displayed on the two digit "debug" display. For these processors, the monitoring utility provided by your motherboard manufacturer on the Driver DVD displays “CPU” temperature in Windows, but is actually the "hottest Core", which is also called "Package" temperature.

Regardless of the Method used, CPU temperature in BIOS is higher than in Windows at idle, because BIOS boots the processor without power saving features and at higher Core voltages to ensure that it will initialize under any conditions.


Section 4 - Package Temperature

Package temperature is the hottest Core.

Package temperature is shown in a few software utilities such as Hardware Monitor - http://www.cpuid.com/softwares/hwmonitor.html - Package temperature can be affected by Intel's on-Die Integrated Graphics Processor Unit (IGPU).


Section 5 - Core Temperature

Also called "Tjunction", this is the temperature measured directly on the hot spots at the transistor junctions inside each Core by individual Digital Thermal Sensors (DTS). Although sensors are factory calibrated by Intel, the specification for DTS accuracy is +/- 5C. This means deviations between the highest and lowest Cores can be up to 10C, so "average" Core temperature is often quite realistic. Sensors are more accurate at high temperatures to protect against thermal damage, but due to calibration issues such as linearity, slope and range, idle temperatures may not be very accurate.

There's a thermal "gradient" between Core temperature and CPU temperature, which is shown on Figure 5 in the following Intel document - http://arxiv.org/ftp/arxiv/papers/0709/0709.1861.pdf - At Default / Auto BIOS settings and factory hardware configuration with 100% Thermal Design Power (TDP), Core temperature is 5C higher than the Tcase Specification. This means that whatever the Tcase Specification is for your CPU, add 5C to get the corresponding value for Core temperature.

Note: For 7th Generation, the Thermal Specification "Tcase" has been replaced with "Tjuction".

Core temperature is the standard for thermal measurement.

Core temperatures respond instantly to changes in load.

Intel’s specification for DTS sensor response time is 256 milliseconds, or about 1/4th of a second. Since Windows has dozens of Processes and Services running in the background, it’s normal to see rapid and random Core temperature fluctuations, especially during the first few minutes after startup.

Here's the recommended operating range for Core temperature:

80C Hot (100% Load)
75C Warm
70C Warm (Heavy Load)
60C Norm
50C Norm (Medium Load)
40C Norm
30C Cool (Idle)
25C Cool

Core temperatures up to 80C are safe.

Your highest temperatures will occur when running test utilities. Temperatures are typically lower during real-world everyday workloads such as processor intensive applications or gaming.

Here’s a list of environment and hardware variables that affect Core temperature:

Ambient temperature
CPU cooler
Thermal Interface Material
Hyperthreading
Core voltage
Core speed
Memory
Computer location
Case design
Fans & ventilation
Cable management
GPU cooler
SLI / CrossFire

For more information see Section 15 - Improving Temperatures.


Section 6 - Throttle Temperature

Also called "Tj Max" (Tjunction Max), this is the Thermal Specification that defines the Core temperature at which the processor will Throttle (reduce clock speed) to protect against thermal damage. Although Intel processors are capable of operating above 90C, we also know that excessive heat damages electronics.

Sustained Core temperatures over 80C are too hot for ultimate stability, performance and longevity.


Section 7 - Relative Temperatures

The relationships between CPU temperatures, Core temperatures and Throttle temperatures are shown below for several popular Quad Core processors, including Thermal Design Power (TDP) and idle Power. All values are based on Intel documentation.

-> Core i

Note: For 7th Generation, Intel’s Product Information website has replaced the Thermal Specification "Tcase" with "Tjuction", which is defined as maximum junction temperature, or "Tj Max". As with prior Generations, Tcase is shown in the Datasheet (see Section 17).

7th Generation 14 nanometer i7 7700K / i5 7600K (TDP 91W / Idle 2W):
Tcase (CPU temp) = 64C
Tjunction (Core temp) = 69C
Tj Max (Throttle temp) = 100C

6th Generation 14 nanometer i7 6700K / i5 6600K (TDP 91W / Idle 2W):
Tcase (CPU temp) = 64C
Tjunction (Core temp) = 69C
Tj Max (Throttle temp) = 100C

5th Generation 14 nanometer i7 5775C / i5 5675C (TDP 65W / Idle 2W):
Tcase (CPU temp) = 71C
Tjunction (Core temp) = 76C
Tj Max (Throttle temp) = 96C

4th Generation 22 nanometer i7 4790K (TDP 88W / Idle 2W):
Tcase (CPU temp) = 74C
Tjunction (Core temp) = 79C
Tj Max (Throttle temp) = 100C

4th Generation 22 nanometer i5 4690K (TDP 88W / Idle 2W),
4th Generation 22 nanometer i7 4770K / i5 4670K (TDP 84W / Idle 2W):
Tcase (CPU temp) = 72C
Tjunction (Core temp) = 77C
Tj Max (Throttle temp) = 100C

3rd Generation 22 nanometer i7 3770K / i5 3570K (TDP 77W / Idle 6W):
Tcase (CPU temp) = 67C
Tjunction (Core temp) = 72C
Tj Max (Throttle temp) = 105C

2nd Generation 32 nanometer i7 2700K / i5 2550K (TDP 95W / Idle 8W):
Tcase (CPU temp) = 72C
Tjunction (Core temp) = 77C
Tj Max (Throttle temp) = 98C

Previous (1st) Generation 32 nanometer i7 860 / i5 760 (TDP 95W / Idle 12W):
Tcase (CPU temp) = 72C
Tjunction (Core temp) = 77C
Tj Max (Throttle temp) = 100C

Previous (1st) Generation 45 nanometer i7 960 D0 (TDP 130W / Idle 12W):
Tcase (CPU temp) = 67C
Tjunction (Core temp) = 72C
Tj Max (Throttle temp) = 100C

-> Core 2

Legacy 45 nanometer Q9650 E0 (TDP 95W / Idle 16W):
Tcase (CPU temp) = 71C
Tjunction (Core temp) = 76C
Tj Max (Throttle temp) = 100C

Legacy 65 nanometer Q6700 G0 (TDP 95W / Idle 24W):
Tcase (CPU temp) = 71C
Tjunction (Core temp) = 76C
Tj Max (Throttle temp) = 100C


Section 8 - Power and Temperature

The previous Sections have explained Intel’s Specifications, and how temperatures are measured and relate to one another. This Section puts the Specifications into a practical perspective, and explains why Thermal Design Power (TDP), Tcase and Tj Max sometimes seem to conflict with recommended real-world Core temperatures.

Although Intel measures Tcase on the surface of the Integrated Heat Spreader (IHS), they also calculate Tcase Specifications based on a combination of processor TDP and stock cooler TDP, which is expressed in Watts. Different cooler models with different TDP values are packaged with different TDP processors. Several Generations of Quad Core processors were packaged with a universal 95 Watt TDP cooler, but the i7 7700K / 6700K and i5 7600K / 6600K cooler is 130 Watts TDP and is sold separately: Intel’s Skylake Cooler - http://vr-zone.com/articles/this-is-what-intels-first-cpu-cooler-for-skylake-looks-like/97189.html.

Compared below are three Intel processor / cooler combinations with respect to TDP and Tcase Specifications:

Example 1: i7 2700K 95 Watts TDP / Cooler 95 Watts TDP / Difference 0 Watts / Tcase 72C.
Example 2: i7 3770K 77 Watts TDP / Cooler 95 Watts TDP / Difference 18 Watts / Tcase 67C.
Example 3: i7 6700K 91 Watts TDP / Cooler 130 Watts TDP / Difference 39 Watts / Tcase 64C.

When the cooler TDP is higher than the processor TDP, Tcase Specifications are lower, just as when the stock cooler is upgraded to a higher TDP aftermarket cooler, Core temperatures are lower. Tcase Specifications are based on a combination of processor TDP and stock cooler TDP. This is the primary reason why there’s so much variation in Tcase Specifications, and reveals a bigger picture beyond Tcase numbers.

The key word in the term “Thermal Design Power” is Design. i5’s follow the i7 Design just as Pentiums and Celerons follow the i3 Design. The differences are Core Count, Cache, Instruction Sets and Hyperthreading. Processors without Hyperthreading (i5’s, Pentiums and Celerons) run cooler than their counterparts with Hyperthreading (i7’s and i3’s), even if they have the same TDP and Tcase Specifications.

Processors with low Tcase Specifications are just as thermally capable as the i7 4790K with Tcase at 74C, and Tjunction (Core temperature) 5C higher at 79C. Further, mobile processors don’t have an Integrated Heat Spreader, so they don’t have Tcase Specifications; only Tj Max. And since Intel has replaced their Tcase Specification for 7th Generation desktop processors with Tj Max, desktop and mobile Thermal Specifications are now consistent with one another.

Nonetheless, when sustained Core temperatures exceed 80C some CPU's become unstable. Core i 6th and 7th Generation CPU's have Configurable TDP (cTDP) and Scenario Design Power (SDP) which can trigger throttling as low as 80C. Throttle temperature (Tj Max) for certain variants is only 80C. Even if Tj Max for your CPU is 100C, you should not run your processor near Throttle temperature due to “Electromigration” (described below in Section 9).

So regardless of your processor’s microarchitecture, TDP, Tcase and Tj Max Specifications, BIOS settings, overclock, hardware configuration, CPU cooler, Ambient temperature, app or game or stress test workloads or any other variables, here's the bottom line: Core temperatures up to 80C are safe. Sustained Core temperatures over 80C are too hot for ultimate stability, performance and longevity.


Section 9 - Overclocking and Voltage

Overclocking is always limited by two factors; voltage and temperature. No two processors are identical; each processor is unique in voltage tolerance, thermal behavior and overclocking potential, which is often referred to as the "silicon lottery" or luck of the draw. As Core speed (MHz) is increased, Core voltage (Vcore) must also be increased to maintain stability. This increases power consumption (Watts) which increases Core temperatures. Overclocked processors using higher Vcore can run up to 50% above TDP. This is why high TDP air or liquid cooling is critical to keep Core temperatures from exceeding 80C.

Overclocking should not be attempted with Vcore settings in “Auto” because BIOS will apply significantly more voltage than is necessary to maintain stability. Even when using manual Vcore settings, excessive Vcore and temperatures may result in accelerated "Electromigration" - https://www.google.com/?gws_rd=ssl#q=Electromigration

This prematurely erodes the traces and junctions within the processor's layers and nano-circuits, which will eventually result in blue-screen crashes that become increasingly frequent over time. CPU's are more susceptible to Electromigration with each Die-shrink, however, Intel's advances in FinFET technology have improved the voltage tolerance of their 14 nanometer microarchitecture.

Here’s a list of the maximum recommended Vcore settings:

-> Core i

7th Generation 14 nanometer ... 1.400 Vcore
6th Generation 14 nanometer ... 1.400 Vcore
5th Generation 14 nanometer ... 1.400 Vcore
4th Generation 22 nanometer ... 1.300 Vcore
3rd Generation 22 nanometer ... 1.300 Vcore
2nd Generation 32 nanometer ... 1.350 Vcore
Previous (1st) Generation 32 nanometer ... 1.350 Vcore
Previous (1st) Generation 45 nanometer ... 1.400 Vcore

-> Core 2

Legacy 45 nanometer ... 1.400 Vcore
Legacy 65 nanometer ... 1.500 Vcore

When tweaking your processor near it's highest overclock, keep in mind that for an increase of 100 MHz, a corresponding increase of about 50 millivolts (0.050) is needed to maintain stability. If 75 to 100 millivolts or more is needed for the next stable 100 MHz increase, it means your processor is overclocked beyond it's capability.

With high TDP air or liquid cooling you might reach the Vcore limit before 80C. With low-end cooling you’ll reach 80C before the Vcore limit. Regardless, whichever limit you reach first is where you should stop and declare victory. Testing is explained in Sections 11 through 14.

Remember to keep overclocking in perspective. For example, the difference between 4.4 GHz and 4.5 Ghz is less than 2.3%, which has no noticeable impact on overall system performance. It simply isn’t worth pushing your processor beyond recommended Core voltage and Core temperature limits just to squeeze out another 100 MHz.


Section 10 - The TIM Problem

Core i 3rd through 7th Generation processors are very sensitive to small increases in voltage and frequency. When overclocked, temperatures might exceed 80C, so high-end air or liquid cooling is critical. 3rd through 7th Generation processors are more difficult to cool than earlier processors for three reasons:

(1) The 3rd and 4th Generation 22 nanometer Die, and the 5th through 7th Generation 14 nanometer Die have significantly less surface area in contact with the underside of the Integrated Heat Spreader (IHS), than the larger 2nd Generation 32 nanometer Die.

(2) 3rd through 7th Generation processors have more transistors packed into a smaller Die than 2nd Generation processors.

(3) 3rd through 7th Generation processors use Thermal Interface Material (TIM) between the top of the Die and the underside of the IHS. "Indium" solder, which has superior thermal conductivity, was instead used in 2nd Generation and earlier processors, and is used in Intel's "High End Desktop Processors" - http://ark.intel.com/products/family/79318/Intel-High-End-Desktop-Processors#@Desktop

http://i1275.photobucket.com/albums/y446/CompuTronix52/Package_zps43993989.jpg(Illustration from Intel Desktop 4th Gen Intel® Core™ Processors Datasheet, Vol. 1, Figure 24).

Since the bonding material which seals the perimeter of the IHS to the Substrate is slightly too thick, this tends to increase the space between the underside of the IHS and the Die, which can cause the TIM to compress unevenly. The effect of this manufacturing procedure is that many processors show a wide deviation between Core temperatures, or one Core which runs much hotter than it's neighbors.

This has encouraged some overclockers to "de-lid" or remove their processor's IHS, which basically involves thoroughly removing the bonding material, replacing only the TIM and then restoring the IHS. Typical results are significantly lower Core temperatures and less deviation between Cores. Here's an excellent YouTube - http://www.youtube.com/watch?v=XXs0I5kuoX4 - that shows before, how-to, and after. Beware that de-lidding will void your warranty, and you can easily damage or destroy your processor.

Intel has addressed these thermal problems in their Haswell refresh. The Devil's Canyon processors have an improved IHS alloy and a new Polymer TIM. Although the TIM doesn't have the thermal conductivity of Indium solder, temperatures have been improved by a few degrees.

Regardless, 4th Generation processors differ from their 3rd Generation counterparts as they have a Fully Integrated Voltage Regulator (FIVR) on the Die, instead of Voltage Regulators on the motherboard, which increases their TDP and Tcase values. Also, due to a 4.0 GHz Base Clock, 4.4 GHz Turbo Boost and increased Vcore, the 4th Generation 88 Watt Devil's Canyon i7 4790K runs hotter at 100% workload than any of it’s counterparts.

Note: 5th Generation 14 nanometer Broadwell processors also have a FIVR on the Die, but the TDP is much lower at only 65 Watts. 6th and 7th Generation 14 nanometer processors do not have Voltage Regulators on the Die. Even though TDP is 91 Watts, thermal behavior is similar to 3rd Generation Ivy Bridge 77 Watt processors.


Section 11 - Thermal Testing Tools

In order to properly test your Core temperatures, you'll need:

• A trusted analog, digital or IR thermometer to measure Ambient temperature.

You'll also need the following freeware utilities downloaded and installed:

• Core Temp - 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

• Optional; Install Real Temp (developed for Intel processors) to test your Digital Thermal Sensors or monitor your Core temperatures - http://www.techpowerup.com/downloads/2089/real-temp-3-70
• Optional; Install SpeedFan if you’d like to use the “Charts” to see your thermal signatures - http://www.almico.com/sfdownload.php


Section 12 - Thermal Testing Basics

Our modern techno-world runs 24/7/365 on gadgets based on engineering standards and design specifications, so when discussing the topic of processor temperatures, it's extremely important to be very specific. We all remember science class where one of the guiding principles for conducting a controlled experiment, is that it's critical to set up the same conditions and follow the same procedures every time. This minimizes variables so results will be consistent and repeatable.

Here's some reasons why users find processor temperatures confusing:

Terminology and specifications.
Abundance of misinformation.
Inconsistent test procedures.

Since many users take a haphazard approach to testing their rigs with "W" hardware at "X" Ambient temperatures using "Y" stress software with "Z" monitoring utilities resulting in "CPU" or "Package" or "Core" temperatures, it's extremely difficult to compare apples to apples, especially when these variables are not listed in detail.

Under proper test conditions, there are only two relevant values:

Core temperature at steady-state 100% workload.
Core temperature at dead idle.

“Load” or “full load” are popular but misleading user terms which are undefined variables that could mean anything. Gaming, applications, rendering, transcoding, virus scanning and web surfing are partial workloads with fluctuating temperatures which aren’t suitable for testing thermal performance or for accurately comparing Core temperatures. Also, 100% CPU usage does not always equal 100% CPU workload.

Intel tests their processors under carefully controlled conditions at 100% TDP. Prime95 Version 26.6 Small FFT's is the standard for CPU thermal testing, because it's a steady-state 100% workload which runs Core 2 processors and Core i variants with Hyperthreading typically within +/- a few % of TDP at stock settings. No other utility so closely replicates Intel's test conditions. This is also the utility that Real Temp uses to test Core temperature sensors.

Note: Do NOT use versions of Prime95 later than 26.6 on 2nd through 7th Generation i3, i5 or i7 CPU's, which all have AVX (Advanced Vector Extension) instruction sets. Recent versions of Prime95 such as 28.9 run AVX code on the CPU's Floating Point Unit (FPU) which causes unrealistic temperatures up to 20C higher. The FPU test in the utility AIDA64 shows similar results. Core i Pentium and Celeron variants, as well as all Core i Previous (1st) Generation and Core 2 processors are unaffected since they do not have AVX instruction sets.

Sections 13 and 14 will explain how to properly test your rig using standardized methods which minimize hardware, software and environmental variables. Follow the "Setup" in both Sections to replicate Intel's test conditions. Each 10 minute tests will establish valid thermal baselines at steady-state 100% workload and at dead idle.


Section 13 - Thermal Testing @ 100% Workload

Note: Keep in mind that we're thermal testing only. Stability testing is not within the scope of this Guide, which assumes your rig is stable. If you're overclocked, then a combination of stress tests, apps or games must be run to verify CPU stability.

If you’re overclocked and run AVX apps, you may need to reduce Vcore and clock speed and / or upgrade your cooling so that Core temperatures don’t exceed 80C. Recent motherboards address the AVX problem by providing offset adjustments in BIOS. Asus RealBench runs a realistic AVX workload typically within +/- a few % of TDP at stock settings, however, it’s a fluctuating workload for stability testing, which isn’t suitable for CPU thermal testing.

• Asus RealBench - http://rog.asus.com/rog-pro/realbench-v2-leaderboard/

Prime95's default test, Blend, is also a fluctuating workload for testing memory stability, and Large FFT's combines CPU and memory tests. As such, Blend and Large FFT's both have fluctuating workloads which aren’t suitable for CPU thermal testing.

Other stability tests such as Linpack and Intel Burn Test have cycles that peak at 120% workload, which again aren’t suitable for CPU thermal testing. The test utility OCCT runs elements of Linpack and Prime95, which will terminate the CPU tests at 85C.

The "Charts" in SpeedFan span 13 minutes, and show how each test creates different thermal signatures.

http://i1275.photobucket.com/albums/y446/CompuTronix52/SpeedFanTempGuideGraph_zpsd98effba.jpgShown above from left to right: Small FFT's, Blend, Linpack and Intel Burn Test.

Note the steady-state thermal signatures of Small FFT's, which allows accurate measurements of Core temperatures. A steady-state 100% workload is critical for thermal testing.

http://i1275.photobucket.com/albums/y446/CompuTronix52/SmallFFTsIntelETUAIDA64_zps2b0c9ff0.jpgShown above from left to right: Small FFT's, Intel Extreme Tuning Utility CPU Test, and AIDA64 CPU Test.

Intel Extreme Tuning Utility is also a fluctuating workload. Although AIDA64's CPU test is steady-state, the workload is well below TDP, which is insufficient for thermal testing. All other AIDA64 CPU test combinations are fluctuating workloads, which again aren't suitable for thermal testing.

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 Core temperatures can be tested under ideal conditions.

Core temperatures rise and fall with Ambient temperature. Testing at or close to 22C Ambient is preferred so as to provide normal thermal headroom, but is not required. During the summer climate, if adequate A/C isn’t available, then test late at night or early in the morning when Ambient is lowest. When testing above or below 22C, it’s important to "normalize" test results to establish a valid thermal baseline. This minimizes variables so results will be consistent and repeatable.

Summer climates create above normal Ambient which decreases overclocking headroom. For example, if your measured Ambient is 4C above Standard, subtract 4C from your reported Core temperatures to normalize your test results.

Winter climates create below normal Ambient which increases overclocking headroom. For example, if your measured Ambient is 4C below Standard, add 4C to your reported Core temperatures to normalize your test results.

Core temperatures normalized to Standard Ambient are your baseline temperatures. Establishing a baseline is important because as Ambient changes, if you maintain your hardware configuration and BIOS settings, baseline Core temperatures give you a consistent point of reference. You can repeat the test whenever you like, to see if your rig is maintaining it’s thermal performance.

Test:

Run Prime95 v26.6 Small FFT's for 10 minutes, then use your thermometer to measure Ambient. Use Core Temp to measure your Core temperatures.

Results:

Core temperatures up to 80C are safe. If reported Core temperatures exceed 80C, you should reduce Vcore and clock speed and / or improve cooling. Intel’s specification for Digital Thermal Sensor (DTS) accuracy is +/- 5C. This means deviations between the highest and lowest Cores can be up to 10C, so "average" Core temperature is often quite realistic. Also, keep in mind that simultaneously running two or more monitoring utilities can sometimes cause them to interfere with one another, so for accuracy, it's highly recommended to run only one monitoring utility at a time.

On processors with more than 2 Cores, the inner Cores run warmer because they’re insulated by the outer Cores. Here’s the physical layout in 2nd, 3rd and 4th Generation Quad Core processors, and an example of how it typically affects Core temperatures:

IGPU = Not in use (PCIE graphics card in use)
Core #0 = 75C (insulated by IGPU and Core #1)
Core #1 = 78C (insulated by Core #0 and #2)
Core #2 = 76C (insulated by Core #1 and #3)
Core #3 = 71C (insulated by Core #2 only)

Core Average = 75C.

Temperatures are more evenly balanced between Cores on 6th and 7th Generation processors due improvements in physical layout.

Note: When viewing your temperatures in Core Temp, values which reach 81C or higher will change from black to amber, which indicates caution.

Normalize your results to Standard Ambient and record the values for future reference.


Section 14 - Thermal Testing @ Idle

Look closely at the SpeedFan Charts above, where idle temperatures are shown between load temperatures. Note that some Cores have more "range" than others and idle lower. Sensors can be tested with Real Temp. Core temperature sensors are more accurate at high temperatures for Throttle protection, but due to calibration issues such as linearity, slope and range, idle temperatures may not be very accurate.

If "Speedstep", also called Enhanced Intel Speedstep Technology (EIST), is disabled in BIOS, then depending on Vcore and clock speed, idle Power can be nearly 40 Watts, which will result in high idle temperatures, especially when combined with high Ambient temperature.

Setup:

In addition to using the previous Setup in Section 13, Speedstep and all "C" States must be enabled to achieve the lowest possible idle temperatures. Also, if Windows Power Options for "Balanced" or "Power saver" is not set correctly, then Speedstep will not work ... OR ... if Windows Power Options is set to "High performance", then Speedstep will not work because Minimum processor state can‘t be set.

To check this, click on Control Panel, Power Options, then to the right of the selected plan, click on Change plan setting. Next click on Change advanced power settings, then drag the scroll bar down. Click on + next to Processor power management, then click on + next to Minimum processor state. This Setting must be 5%. If it's not, then correct it and click Apply.

Restart into BIOS and confirm that you've saved your settings to a Profile. Next, change all settings to stock (Default / Auto) including SpeedStep, all C States and Vcore, then save and exit. Reboot into Windows and confirm that your rig is at dead idle; no programs running, and off line. No Folding or SETI or "tray-trash" running in the background, and less than 3% CPU Usage under the "Performance" tab in Windows Task Manager.

Use CPU-Z to confirm that Core Voltage and Core Speed has decreased as follows:

-> Core i

7th Generation 14 nanometer ... about 0.7 Volts @ 800 MHz
6th Generation 14 nanometer ... about 0.8 Volts @ 800 MHz
5th Generation 14 nanometer ... about 0.8 Volts @ 800 MHz
4th Generation 22 nanometer ... about 0.8 Volts @ 800 MHz
3rd Generation 22 nanometer ... about 0.9 Volts @ 1600 MHz
2nd Generation 32 nanometer ... about 1.0 Volts @ 1600 MHz
Previous (1st) Generation 32 nanometer ... about 1.0 Volts @ 1600 MHz
Previous (1st) Generation 45 nanometer ... about 1.0 Volts @ 1600 MHz

-> Core 2

Legacy 45 nanometer ... about 1.1 Volts @ 2000 MHz
Legacy 65 nanometer ... about 1.25 Volts @ 1600 MHz

Use Core Temp to confirm that Power has decreased as follows:

-> Core i

7th Generation 14 nanometer ... about 2 Watts
6th Generation 14 nanometer ... about 2 Watts
5th Generation 14 nanometer ... about 2 Watts
4th Generation 22 nanometer ... about 2 Watts
3rd Generation 22 nanometer ... about 6 Watts
2nd Generation 32 nanometer ... about 8 Watts
Previous (1st) Generation 32 nanometer ... about 8 Watts
Previous (1st) Generation 45 nanometer ... about 12 Watts

Note: Idle Volts and Watts may differ depending on BIOS versions and motherboard models. Power (Watts) isn't measured on Previous (1st) Generation Core i Socket 1366 variants and Legacy Core 2 Socket 775 processors, but for general reference, idle power for several popular CPU's is shown in Section 7 - Relative Temperatures.

Test:

Allow your rig to "settle" for 10 minutes, then use your thermometer to measure Ambient. Use Core Temp to measure your Core temperatures.

Results:

Core i 2nd through 7th Generation processors should idle at less than 8C above Ambient. This means at 22C Standard Ambient your Cores should idle just under 30C. Certain Previous (1st) Generation Core i variants and most Legacy Core 2 Socket 775 processors may idle several degrees higher. Many Legacy Core 2 45 nanometer variants have sensors that "stick" in the mid 40's showing false high idle temperatures, and some Core i 6th Generation variants show idle temperatures below Ambient. Idle temperatures may not be very accurate. Better cooling and lower idle Power produce lower idle temperatures.

Normalize your results to Standard Ambient and record the values for future reference. When finished testing, restore your system to it's previous configuration.


Section 15 - Improving Temperatures

Whether your computer is a stock workstation or an overclocked gaming rig, achieving the lowest possible temperatures always depends on components, configuration and airflow. Here's a few thoughts:

• Intel coolers are barely adequate at stock. If you want to overclock then upgrade your cooler.
• Use Manual Vcore settings. Auto applies excess voltage which means more power and heat.
• Memory overclock and XMP Profiles can cause Core i processors to run a few degrees hotter.
• Axial flow graphics cards recirculate heat. Linear flow cards exhaust heat from the case.

Examples:

Axial - http://www.newegg.com/Product/Product.aspx?Item=N82E16814487248
Linear - http://www.newegg.com/Product/Product.aspx?Item=N82E16814487247

• Axial cards work well with a liquid cooled CPU. Linear cards work well with an air cooled CPU.
• SLI / CrossFire works best with Linear cards. Axial cards dump massive heat in your case.
• A hot case stresses hard drives, memory, chipsets, voltage regulators and power supply.
• High performance computers need unrestricted airflow in and out, so location is critical.
• Load temperatures that drop over a degree or two with case covers off means poor airflow.
• Good cable management creates good airflow. Use zip-ties, patience and attention to detail.
• Quality fans are important, but if you want a quiet computer then consider a fan controller.
• If your CPU is too hot, you may need to adjust the fan curve in BIOS or your software utility.
• If your case just doesn't breathe well, then perhaps it's time to upgrade to one that does.
• If your rig runs 24/7, then dust is accumulating and moving parts are wearing prematurely.
• Clean the dust out of your rig. Perform regular Planned Maintenance Inspections (PM's).
• Replace your TIM. Most Thermal Interface Material typically begins to fail after 2 years.

Thermal Interface Material (TIM):

Thermal Paste Comparison, Part One: Applying Grease And More - http://www.tomshardware.com/reviews/thermal-paste-heat-sink-heat-spreader,3600.html
Thermal Paste Comparison, Part Two: 39 Products Get Tested - http://www.tomshardware.com/reviews/thermal-paste-performance-benchmark,3616.html

The proper installation of Intel's stock cooler:

Intel Stock Cooler Installation Guide - http://www.tomshardware.com/forum/338655-28-intel-stock-cooler-installation-guide

Choosing an aftermarket cooler:

Air Cooling vs Water Cooling : Things You Need To Know - http://www.tomshardware.com/forum/id-2196038/air-cooling-water-cooling-things.html
Alternatives to the Hyper 212+/Evo for budget cooling - http://www.tomshardware.com/forum/id-2705157/alternatives-hyper-212-evo-budget-cooling.html


Section 16 - Summary

• Standard Ambient temperature is 22C.
• Ambient affects all computer temperatures.
• No temperatures can be less than or equal to Ambient.
• As Ambient increases, thermal headroom decreases.
• BIOS or CPU temperature may not be accurate.
• Package temperature is the hottest Core.
• Core temperature is the standard for thermal measurement.
• Core temperatures respond instantly to changes in load.
• Core temperatures up to 80C are safe.
Sustained Core temperatures over 80C are too hot.
• Excessive Vcore and temperatures accelerate electromigration.
• Prime95 v26.6 Small FFT's is the standard for thermal testing.
• Deviations between highest and lowest Cores may be 10C.
• Core temperature sensors are more accurate at high temperatures.
• Idle temperatures may not be very accurate.
• Sensors can be tested with Real Temp.


Section 17 - References

• Intel® Processor Temperature FAQ - http://www.intel.com/support/processors/sb/CS-033342.htm

• Intel® Product Information - http://ark.intel.com/

• Intel® Core™ Processors Technical Resources - http://www.intel.com/content/www/us/en/processors/core/core-technical-resources.html

• 7th Generation Intel® Processor Datasheet for S-Platforms, Volume 1 - http://www.intel.com/content/www/us/en/processors/core/7th-gen-core-family-desktop-s-processor-lines-datasheet-vol-1.html

• Intel® Core™ i7 Processor Family 6xx0 for LGA2011-v3 Socket Datasheet, Volume 1 - http://www.intel.com/content/www/us/en/processors/core/core-i7-6xxx-lga2011-v3-datasheet-vol-1.html

• 6th Generation Intel® Processor Datasheet for S-Platforms, Volume 1 - http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/desktop-6th-gen-core-family-datasheet-vol-1.pdf

• Desktop 5th Generation Intel® Core™ Processor Family Datasheet, Volume 1 - http://www.intel.com/content/www/us/en/processors/core/desktop-5th-gen-core-family-datasheet-vol-1.html

• Intel® Core™ i7 Processor Family 5xx0 for LGA2011-v3 Socket Datasheet, Volume 1 - http://www.intel.com/content/www/us/en/processors/core/core-i7-lga2011-3-datasheet-vol-1.html

• Desktop 4th Generation Intel® Core™ Processor Family, Desktop Intel® Pentium® Processor Family, and Desktop Intel® Celeron® Processor Family Datasheet, Volume 1 - http://www.intel.com/content/www/us/en/processors/core/4th-gen-core-family-desktop-vol-1-datasheet.html?wapkw=328897

• Desktop 3rd Generation Intel® Core™ Processor Family, Desktop Intel® Pentium® Processor Family, and Desktop Intel® Celeron® Processor Family Datasheet, Volume 1 - http://www.intel.com/content/www/us/en/processors/core/3rd-gen-core-desktop-vol-1-datasheet.html

• 2nd Gen Intel® Core™ Processor, LGA1155 Socket: Thermal Guide - http://www.intel.com/content/www/us/en/processors/core/2nd-gen-core-lga1155-socket-guide.html

• Intel® Core™ i5-600/i3-500 Desktop Processor: Thermal Design Guide - http://www.intel.com/content/www/us/en/intelligent-systems/foxhollow/core-i5-600-i3-500-pentium-6000-desktop-lga1156-tmdg.html

• CPU Monitoring With DTS/PECI - http://www.intel.com/content/www/us/en/embedded/testing-and-validation/cpu-monitoring-dts-peci-paper.html

• Intel® Core™ i7-800 and i5-700 Desktop Processor Series Datasheet, Volume 1 - http://www.intel.com/content/www/us/en/intelligent-systems/piketon/core-i7-800-i5-700-desktop-datasheet-vol-1.html

• Intel® Core™ i7-900 Desktop Processor Extreme Edition Series and Intel® Core™ i7-900 Desktop Processor Series Datasheet, Volume 1 - http://www.intel.com/content/www/us/en/processors/core/core-i7-900-ee-and-desktop-processor-series-datasheet-vol-1.html

• Intel® Core™2 Extreme Processor QX9000 Series, Intel® Core™2 Quad Processor Q9000, Q9000S, Q8000, and Q8000S Series Datasheet - http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/core2-qx9000-q9000-q8000-datasheet.pdf

• Intel® Core™2 Extreme Quad-Core Processor QX6000 Sequence and Intel® Core™2 Quad Processor Q6000 Sequence Datasheet - http://download.intel.com/design/processor/datashts/31559205.pdf

• Temperature measurement in the Intel® CoreTM Duo Processor - http://arxiv.org/ftp/arxiv/papers/0709/0709.1861.pdf

_________________________________________________


I hope this Guide has answered your questions, and has provided you with a clear perspective of Intel processor temperatures.

Thank you for reading.

CompuTronix :sol:


About the Guide

The Intel Temperature Guide is the result of more than 5,000 hours of ongoing research and hands-on testing spanning over 10 years. It is frequently updated as new information becomes available.


About the Author

Based in Fort Lauderdale, Florida, USA. Interests include computers, electronics, technology, sailing and flying.

Experience: Building and overclocking PC’s since 1994.
Background: Medical Imaging Engineer, Aviation Electronics, US Navy Veteran.
Education: BSEET, numerous technical certifications in specialized military and industrial electronics.

Published: 2007 - Core 2 Duo Temperature Guide, 2007 - Core 2 Quad and Duo Temperature Guide, 2009 - Core i and Core 2 Temperature Guide, 2013 - Intel Temperature Guide.
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