Sticky: Core i7 and Core 2 Temperature Guide

Core i7 and Core 2 Temperature Guide - by CompuTronix

Copyright © 2009
All rights reserved.
Rev. 90512

Preface:

The purpose of this Guide is to provide overclocking enthusiasts with an understanding of thermal relationships, so that temperatures can be uniformly tested, accurately calibrated, and properly monitored. This Guide supports air cooled Core i7 and Core 2 desktop processors. All temperatures are referenced to Standard Ambient 22c.

Scope:

This Guide is intended for intermediate to advanced users. Although certain strict definitions have been relaxed to simplify concepts, this Guide contains detailed technical information. Knowledge of hardware configurations, BIOS settings, motherboard manuals and terminology is required, as well as familiarity with CPU-Z, Prime95 and SpeedFan.

Sections:

1: Introduction
2: Specifications
3: Interpretation
4: Thermal Flow
5: Findings
6: Scale
7: Parameters
8: Tools
9: Calibrations
10: Results and Variables
11: Offsets
12: Overclocking
13: Heat Score
14: Recommendations
15: Troubleshooting
16: Comments

Section 1: Introduction

Core i7 and Core 2 processors have 2 different types of temperature sensors; a CPU case (not computer case) Thermal Diode centered under the Cores, and Digital Thermal Sensors located on each Core. The case Thermal Diode measures Tcase (Temperature case), which is CPU temperature, and the Digital Thermal Sensors measure Tjunction (Temperature junction), which is Core temperature. Since these sensors measure 2 distinct thermal levels, there is a 5c temperature difference between them, which is Tcase to Tjunction Gradient. Ci7’s and C2Q's have 1 Tcase and 4 Tjunction sensors, while C2D's have 1 Tcase and 2 Tjunction sensors. Uncalibrated default temperatures are seldom accurate.

Intel provides complete specifications for Tcase (CPU temperature), but only partial specifications for Tjunction (Core temperature), which has caused much confusion and debate in the overclocking community concerning test methods, temperature monitoring utilities and accuracy. The monitoring utilities provided by motherboard manufacturers monitor CPU temperature, while some popular freeware utilities monitor Core temperatures. The most accurate Core temperature monitoring utility available is Real Temp - http://www.techpowerup.com/realtemp/ - which has several unique and innovative features, and is recommended for users interested in monitoring Core temperatures only.

SpeedFan monitors Tcase (CPU temperature) and Tjunction (Core temperature), which can be calibrated for each sensor, while also providing a full compliment of peripheral temperatures, voltages and fan speeds. SpeedFan is very flexible and configurable, which includes thermal alarm settings and graphical charts, as well as many other excellent automated features for creating a cool yet quiet overclocked computer. When configured with this Guide, SpeedFan is recommended for overclocking enthusiasts interested in achieving the most precise custom temperature calibrations, while observing vital system performance information.

Section 2: Specifications

Since temperatures can be confusing to decipher and compare, it is very important to be specific, so when listing Idle & Load test Results, it is also necessary to list the Variables as shown below:

Results

Tcase = Idle & Load
Tjunction = Idle & Load

Variables

Ambient = Room Temp
Chipset = Model
i7 / C2 = Model
CPU Cooler = Model
Frequency = CPU Clock
Load = Test Software
Motherboard = Model
Stepping = Revision
Vcore = CPU Voltage

CPU's can be identified by the product code on the retail box, the Integrated Heat Spreader on the CPU, and by CPU-Z. Use CPU-Z (see Section 8) to read the Revision field below the Stepping field, then record the characters. Use the following link to match the CPU with Intel's Spec# for VID Voltage Range, Core Stepping, Thermal Design Power, and Thermal Specification (which is maximum CPU temperature, not maximum Core temperature).

• Intel Processor Spec Finder: http://processorfinder.intel.com/Default.aspx

Intel Thermal Specifications:

(<>) The thermal specification shown is the maximum case temperature at the maximum Thermal Design Power (TDP) value for that processor. It is measured at the geometric center on the topside of the processor integrated heat spreader.

(><) For processors without integrated heat spreaders such as mobile processors, the thermal specification is referred to as the junction temperature (Tj). The maximum junction temperature is defined by an activation of the processor Intel® Thermal Monitor. The Intel Thermal Monitor's automatic mode is used to indicate that the maximum TJ has been reached.

Additional Specifications:

Standard Ambient = 22c
Thermal Diode Accuracy = +/-1c

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 Intel laboratory testing only, CPU temperature is instead measured using a Thermal Diode centered under the Cores. Maximum case temperature (Tcase Max) is determined by Spec#. The CPU case Thermal Diode is how Tcase is measured, and is the CPU temperature displayed in BIOS and SpeedFan.

• Tcase Max is a specification, Tcase is a temperature.

(><) The second part of the spec refers to mobile processors without Integrated Heat Spreaders (IHS). Although desktop processors have an IHS, both variants measure the hot spots on each Core using Digital Thermal Sensors (DTS). Maximum junction temperatures (Tjunction Max) are determined by Intel factory Calibrations. The Digital Thermal Sensors are how Tjunction is measured, and are the Core temperatures displayed in SpeedFan.

• Tjunction Max is a specification, Tjunction is a temperature.

Section 4: Thermal Flow

Heat originates within the Cores, where Tjunction sensors are located on the hot spots of each Core. Most of the heat dissipates from the top of the Cores through the Integrated Heat Spreader and CPU cooler to air inside the computer. Some of the heat dissipates from the bottom of the Cores through the CPU case, which creates a 5c thermal Gradient toward the center of the substrate, where the Tcase sensor is located. This heat then dissipates through the socket and motherboard to air inside the computer. Safe and sustainable temperatures are determined by CPU cooling efficiency, computer case cooling efficiency, Ambient temperature, Vcore, clock speed and Load.

• Tjunction is higher than Tcase.

• Tcase is higher than Ambient.

Section 5: Findings

(A) Tcase is acquired on the CPU substrate 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. Motherboard BIOS Calibration affects the accuracy of Tcase, or CPU temperature.

(B) Tjunction is acquired on the Cores from Thermal Diodes as analog levels, which are converted to digital values by the Digital Thermal Sensors (DTS) on each Core. The digital values are Factory Calibrated and displayed by temperature software. Intel 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) The Specification that Intel supports in the Processor Spec Finder for Core i7 and Core 2 desktop processors is Tcase Max, not Tjunction Max. Ambient to Tcase Delta has known Offsets which vary with power dissipation and cooler efficiency, and is Calibrated at Idle using a standardized Test Setup.

• Ambient is used to Calibrate Tcase Idle.

(E) Intel provides only partial documentation for Tjunction Max on desktop processors. For Throttling and thermal Shutdown protection, Intel uses the Digital Thermal Sensors (DTS) to monitor Delta to Tjunction Max, which is a relative value that varies from Core to Core, and is not an absolute temperature.

(F) Tjunction Max must be known to calculate absolute Core temperature, which is Tjunction. Popular temperature monitoring utilities may incorrectly estimate undisclosed Tjunction Max values, which results in excessive Core temperatures and inconsistent Tcase to Tjunction Gradients among Ci7 and C2 variants.

(G) Existing test data from several Intel papers - http://arxiv.org/ftp/arxiv/papers/0709/0709.1861.pdf - as well as numerous independent sources show Tcase to Tjunction Gradient has a known Offset which is 5c, and is Calibrated at Load using a standardized Test Setup.

• Tcase Load is used to Calibrate Tjunction Load.

Section 6: Scale

Safe and sustainable temperatures vary according to Spec#. The temperature Scales shown below illustrate the Delta between Idle and Load, and the 5c Gradient between Tcase and Tjunction. Although the 5c Gradient is relatively consistent, Tcase and Tjunction tend to converge at Idle and diverge at Load due to Variables such as Vcore and CPU cooler efficiency. Low Vcore and clock may cause Tcase to Tjunction Gradient to indicate less than 4c at Idle, while high Vcore and overclock may cause the Gradient to exceed 6c at Load.

If temperatures increase beyond Hot Scale, then a few degrees below Tjunction Max, Throttling is activated. The Digital Thermal Sensors (DTS) are used to trigger Intel's TM1 and TM2 technologies for frequency, multiplier and Vcore Throttling within individual Cores. If Core temperatures exceed Tjunction Max, then Shutdown occurs. Since Tcase indicates CPU substrate temperature only, it is not used for Throttle or Shutdown activation, however, as Tcase Max will be exceeded before Tjunction Max is reached, Tcase Max is always the limiting thermal specification.

Use CPU-Z (see Section 8) to read processor information including the Revision field below the Stepping field, then choose a Scale below which matches the CPU being tested. Scales are ordered from highest to lowest Tcase Max, according to Intel Thermal Specifications.

Scale 1: Quad
Q9550S: Tcase Max 76c, Stepping E0, TDP 65W, Idle 16W
Q9400S: Tcase Max 76c, Stepping R0, TDP 65W, Idle 16W
Q8x00S: Tcase Max 76c, Stepping R0, TDP 65W, Idle 16W

-Tcase/Tjunction-
--75--/--80--80--80--80-- Hot
--70--/--75--75--75--75-- Warm
--65--/--70--70--70--70--Safe <--
--25--/--30--30--30--30-- Cool

Scale 2: Duo
E8x00: Tcase Max 74c, Stepping E0, TDP 65W, Idle 8W
E7x00: Tcase Max 74c, Stepping R0, TDP 65W, Idle 8W
E7x00: Tcase Max 74c, Stepping M0, TDP 65W, Idle 8W
E5x00: Tcase Max 74c, Stepping R0, TDP 65W, Idle 8W
E5200: Tcase Max 74c, Stepping M0, TDP 65W, Idle 8W
E4700: Tcase Max 73c, Stepping G0, TDP 65W, Idle 8W
E4x00: Tcase Max 73c, Stepping M0, TDP 65W, Idle 8W
E2xx0: Tcase Max 73c, Stepping M0, TDP 65W, Idle 8W
E8600: Tcase Max 72c, Stepping E0, TDP 65W, Idle 8W
E8xx0: Tcase Max 72c, Stepping C0, TDP 65W, Idle 8W
E6x50: Tcase Max 72c, Stepping G0, TDP 65W, Idle 8W
E6540: Tcase Max 72c, Stepping G0, TDP 65W, Idle 8W

-Tcase/Tjunction-
--70--/--75--75-- Hot
--65--/--70--70-- Warm
--60--/--65--65--Safe <--
--25--/--30--30-- Cool

Scale 3: Quad
Q9x50: Tcase Max 71c, Stepping E0, TDP 95W, Idle 16W
Q9x50: Tcase Max 71c, Stepping C1, TDP 95W, Idle 16W
Q9400: Tcase Max 71c, Stepping R0, TDP 95W, Idle 16W
Q9300: Tcase Max 71c, Stepping M1, TDP 95W, Idle 16W
Q8x00: Tcase Max 71c, Stepping R0, TDP 95W, Idle 16W
Q8200: Tcase Max 71c, Stepping M1, TDP 95W, Idle 16W
Q6x00: Tcase Max 71c, Stepping G0, TDP 95W, Idle 16W

-Tcase/Tjunction-
--70--/--75--75--75--75-- Hot
--65--/--70--70--70--70-- Warm
--60--/--65--65--65--65--Safe <--
--25--/--30--30--30--30-- Cool

Scale 4: Quad
Ci7 9xx: Tcase Max 68c, Stepping C0, TDP 130W, Idle 16W<--Core i7
QX6x50: Tcase Max 65c, Stepping G0, TDP 130W, Idle 16W
QX6800: Tcase Max 65c, Stepping G0, TDP 130W, Idle 16W
QX6700: Tcase Max 65c, Stepping B3, TDP 130W, Idle 24W
QX9650: Tcase Max 64c, Stepping C1, TDP 130W, Idle 16W
QX9650: Tcase Max 64c, Stepping C0, TDP 130W, Idle 16W
QX9775: Tcase Max 63c, Stepping C0, TDP 150W, Idle 16W

-Tcase/Tjunction-
--65--/--70--70--70--70-- Hot
--60--/--65--65--65--65-- Warm
--55--/--60--60--60--60--Safe <--
--25--/--30--30--30--30-- Cool

Scale 5: Quad
Q6600: Tcase Max 62c, Stepping B3, TDP 105W, Idle 24W

-Tcase/Tjunction-
--60--/--65--65--65--65-- Hot
--55--/--60--60--60--60-- Warm
--50--/--55--55--55--55--Safe <--
--25--/--30--30--30--30-- Cool

Scale 6: Duo
E6x00: Tcase Max 61c, Stepping L2, TDP 65W, Idle 12W
E4x00: Tcase Max 61c, Stepping L2, TDP 65W, Idle 12W
E21x0: Tcase Max 61c, Stepping L2, TDP 65W, Idle 8W
X6800: Tcase Max 60c, Stepping B2, TDP 75W, Idle 24W
E6x00: Tcase Max 60c, Stepping B2, TDP 65W, Idle 24W (Spec# SL9Sx)
E6x00: Tcase Max 60c, Stepping B2, TDP 65W, Idle 12W (Spec# SL9Zx)
E6x20: Tcase Max 60c, Stepping B2, TDP 65W, Idle 12W

-Tcase/Tjunction-
--60--/--65--65-- Hot
--55--/--60--60-- Warm
--50--/--55--55--Safe <--
--25--/--30--30-- Cool

Scale 7: Quad
QX9770: Tcase Max 56c, Stepping C1, TDP 136W, Idle 16W
QX6800: Tcase Max 55c, Stepping B3, TDP 130W, Idle 24W

-Tcase/Tjunction-
--55--/--60--60--60--60-- Hot
--50--/--55--55--55--55-- Warm
--45--/--50--50--50--50--Safe <--
--25--/--30--30--30--30-- Cool

Section 7: Parameters

(A) NO temperatures can be less than Ambient.

(B) Standard Ambient temperature is specified at 22c.

(C) All temperatures increase as Ambient, clock and Vcore increase.

(D) Tcase to Tjunction Gradient is 5c during Prime95 Small FFT's at stock settings.

(E) Tcase and Tjunction should not exceed Hot Scale during Prime95 Small FFT's.

(F) Vcore Load should not exceed 1.375 volts on Core i7 processors.

(G) Vcore Load should not exceed 1.3625 volts on 45nm processors.

(H) Vcore Load should not exceed 1.5 volts on 65nm processors.

(I) Idle to Load Delta may exceed 25c when overclocked.

Section 8: Tools

Hardware:

• A trusted indoor analog or digital thermometer will be needed to measure Ambient. The accuracy of this device and measurement will determine the overall accuracy of the Calibrations.

Software:

CPU-Z and SpeedFan will be used to Calibrate Tcase at Idle. Prime95 will be used in addition to CPU-Z and SpeedFan to Calibrate Tjunction at Load. SpeedFan will then be used to permanently monitor temperatures.

Use the following links to download and install these utilities:

• CPU-Z 1.51: http://www.cpuid.com/cpuz.php

• Prime95 25.9: http://mersenne.org/freesoft/#newusers

• SpeedFan 4.38: http://www.almico.com/speedfan.php

Note 1: Prime95 - When run for the first time, it is necessary to click on Advanced, then click on Round off checking so that errors caused by instabilities will be flagged as they occur. Prime95 will automatically thread all Cores, and will expose insufficient CPU cooling and computer case cooling, or excessive Vcore and overclock. At no other time will a CPU be as heavily loaded, or display higher temperatures, even when OC'd during worst-case loads such as gaming or video editing. Prime95 can be used with SpeedFan to observe CPU temps, while stress testing for system stability. During single threaded gaming and applications, Core 0 typically carries heavier loads and higher temps than other Cores.

Note 2: SpeedFan - Very flexible and configurable, SpeedFan is the preferred temperature monitoring utility because Tcase and Tjunction can be Calibrated. SpeedFan detects and labels thermal sensors according to various motherboard, chipset and super I/O chip configurations, so the label for Tcase can be CPU, Temp 1, Temp 2, or Temp 3. Even if Tcase is labeled as CPU, it is still necessary to confirm the identity of Tcase prior to performing Calibrations.

• Repeatedly start and stop Prime95 Small FFT's at 15 second intervals, while observing which SpeedFan temperature scales with an Idle to Load Delta similar to the Cores. This will identify the label corresponding to Tcase. Labels can later be renamed using the Configure button. See Section 11.

If a temperature shows a flame icon, this indicates alarm limits which require adjustment. Use the Configure button to set CPU and Core temp alarms to Warm Scale. If a temperature shows Aux 127, this is simply an unassigned input which can be disabled using the Configure button. See Section 11.

Section 9: Calibrations

Default temperatures are rarely accurate. The following two part procedure is designed to achieve two objectives:

• Provide minimum Ambient to Tcase Delta for accurate Tcase Idle Calibration.

• Provide maximum Tcase to Tjunction Gradient for accurate Tjunction Load Calibration.

Note: It is preferred, but not required, that Calibrations be conducted as close to 22c Standard Ambient as possible, which provides a normal temperature ceiling, and maintains environmental consistency for comparing Idle and Load temperatures among processor variants and system platforms.

Prerequisites:

(A) CPU cooler correctly installed.

(B) Print this Section to use for BIOS settings and Calibrations.

(C) Record or photo or Save Profile all BIOS settings for quick restore when Calibrations are complete.

(D) Follow the Test Setup: (Standardized configuration for maximum cooling at Auto Vcore, Frequency and Multiplier).

Computer Case Covers = Removed
Computer Case Fans = Manual 100% RPM
CPU Fan = Manual 100% RPM
CPU Frequency = Auto (See Note 1: below) **
CPU Internal Thermal Control = Enabled
Enhanced C1 Control (C1E) = Enabled
Internet = Disconnected
Memory Frequency = Auto
PECI (If Equipped) = Enabled
Speedstep (EIST) = Enabled
Vcore = Auto (See Note 1: below) **
Vdimm = Auto
Windows Programs = Closed

Part 1: Calibration - Tcase Idle (Uses maximum cooling at minimum Vcore, Frequency and Multiplier)

** Note 1: If BIOS does not respond properly to Auto Vcore, Frequency and Multiplier settings, then use an appropriate combination of manual settings to provide the following in CPU-Z:

Core Voltage = 1.100 V
Core Speed = 1600 Mhz (Core i7 processors)
Core Speed = 1600 Mhz (Core 2 - 65 nm processors)
Core Speed = 2000 Mhz (Core 2 - 45 nm processors)

(A) Measure Ambient near the computer case air intake, clear of warm exhaust. A trusted indoor analog or digital thermometer will suffice. The accuracy of this device and measurement will determine the overall accuracy of the Calibrations.

(B) Boot into Windows. Close all programs, background processes, Screen Savers, SETI, Folding and Tray software. Press Ctrl-Alt-Delete, click on Task Manager, then click on the Performance tab to confirm CPU Usage is less than 1%. Use the Applications and Processes tabs to close programs if necessary.

(C) Open CPU-Z and SpeedFan. Observe CPU-Z for Intel's Speedstep to decrease Core Voltage, Core Speed and Multiplier to minimum values. Observe SpeedFan, allow 10 minute at Idle to ensure that temperatures decrease to minimums, then record Tcase Idle.

• Tcase Idle = Ambient + Z.

"Z" compensates for Idle power dissipation and CPU cooler efficiency. Use the Scales in Section 6 to find "X" Idle Power, use the links in Section 14 to find "Y" Cooler Efficiency, use the Table and Formula below to find "Z", then add Ambient to find Tcase Idle.

• Idle Power and Cooler Efficiency Table:

X = 2 . . . Idle Power: 8W . . . . Y = 2 . . . . Cooler Efficiency: High-end
X = 3 . . . Idle Power: 12W . . . Y = 3 . . . . Cooler Efficiency: High mid-range
X = 4 . . . Idle Power: 16W . . . Y = 4 . . . . Cooler Efficiency: Mid-range
. . . . . . . . . . . . . . . . . . . . . . . . . Y = 5 . . . . Cooler Efficiency: Low mid-range
X = 6 . . . Idle Power: 24W . . . Y = 6 . . . . Cooler Efficiency: Low-end / Stock Intel

• Tcase Idle Formula:

(X + Y) / 2 = Z + Ambient = Tcase Idle.

Note 2: CPU and cooler combinations which are both lapped may subtract 1c from Tcase Idle.

Example 1: Duo

Idle Power: E2160, Stepping M0, Idle 8W, so X = 2.
Cooler Efficiency: Mid-range – Arctic Cooling Freezer 7 Pro, so Y = 4.
(2 + 4) / 2 = 3, so Z = 3.
Ambient = 22c.
3 + 22 = 25, so Tcase Idle = 25c.

Example 2: Quad

Idle Power: i7 920, Stepping C0, Idle 16W, so X = 4.
Cooler Efficiency: High-end – Xigmatek HDT-S1283, so Y = 2.
(6 + 2) / 2 = 3 so Z = 3.
Ambient = 22c.
3 + 22 = 25, so Tcase Idle = 25c.

(D) Configure Offset correction as shown in Section 11. Since the Tcase sensor was designed to be linear from Idle to Load, Tcase Load will also be accurate.

Part 2: Calibration - Tjunction Load (Uses maximum cooling at Stock Vcore, Frequency and Multiplier)

** Note 1: If BIOS does not respond properly to Stock Vcore, Frequency and Multiplier settings, then use an appropriate combination of manual settings to provide the following in CPU-Z:

Core Voltage = 1.250 V
Core Speed = Stock Mhz

(A) Start Prime95 Small FFT's. Observe CPU-Z for Intel's Speedstep to increase Core Voltage, Core Speed and Multiplier to Stock values. Observe SpeedFan. Heat saturation is typically reached within 7 to 8 minutes, so allow 10 minutes at Load to assure that temperatures increase to maximums, then record Tjunction for each Core.

• Tjunction Load = Tcase Load + 5c.

Example 1: Duo

Tcase Load = 45c
Tjunction Load = 50c

-Tcase/Tjunction-
--45--/--50--50--

Example 2: Quad

Tcase Load = 45c
Tjunction Load = 50c

-Tcase/Tjunction-
--45--/--50--50--50--50--

(B) Configure Offset corrections as shown in Section 11.

(C) Stop Prime95, then allow the system to Idle for 10 minutes. Tjunction Idle should be ~ 4c higher than Tcase Idle.

Note 2: Tjunction sensors were designed to be linear at high temperatures for Throttle and Shutdown protection, so Tjunction Idle could indicate too low or too high. Many 45 nanometer variants have faulty sensors that "stick" and might not Idle below 50c. Sensors can be tested using Real Temp - http://www.techpowerup.com/realtemp/

• If Tjunction Idle is not ~ 4c higher than Tcase Idle, then use Tcase Idle for accurate Idle temperature.

(D) Repeat Item (A) and allow Prime95 to run past 10 minutes while reinstalling covers. If temperatures increase, then computer case cooling should be improved.

(E) Restore the system to original or custom BIOS settings and hardware / software preferences.

Section 10: Results and Variables

Prime95 Small FFT's should verify that Tjunction Load = Tcase Load + 5c. If temperatures do not meet the Parameters, then check the Test Setup and repeat Parts 1 and 2. Remember that Tcase and Tjunction tend to converge at Idle and diverge at Load due to Variables such as Vcore and CPU cooler efficiency. Low Vcore and clock may cause Tcase to Tjunction Gradient to indicate less than 4c at Idle on an E2xxx, while a heavily overclocked Core i7 with high Vcore may exceed Tcase to Tjunction Gradient of 6c at Load.

If temperatures are allowed to increase beyond Hot Scale, then a few degrees below Tjunction Max Throttling is activated. If Core temperatures exceed Tjunction Max, then Shutdown occurs. Since Tcase Max will be exceeded before Tjunction Max is reached, Tcase Max is always the limiting thermal specification.

• It is not recommended to continually operate processors, overclocked or stock, at Hot Scale for reasons of stability and longevity.

The following Examples each represent typical overclocked systems, which have moderately high Vcore settings, yet still maintain Safe temperatures at 100% Workload. Note that Tcase to Tjunction Gradient shows 6c at Load due to high Vcore. This is normal and expected, since 5c was Calibrated using a Test Setup standardized for maximum cooling capacity at Stock Vcore, Frequency and Multiplier settings.

Example 1: Duo

Tcase = 29c Idle, 60c Load (SpeedFan: CPU or Temp x)
Tjunction = 33c Idle, 66c Load (SpeedFan: Core x)

Ambient = 22c
Chipset = P45
CPU = E8400
CPU Cooler= Arctic Cooling Freezer 7 Pro
Frequency = 4.0 Ghz
Load = Prime95 - Small FFT's - 10 minutes
Motherboard = Asus P5Q Deluxe
Stepping = C0
Vcore Load = 1.350

Example 2: Quad

Tcase = 31c Idle, 60c Load (SpeedFan: CPU or Temp x)
Tjunction = 35c Idle, 66c Load (SpeedFan: Core x)

Ambient = 22c
Chipset = X58
CPU = i7 920
CPU Cooler= Xigmatek HDT-S1283
Frequency = 3.8 Ghz
Load = Prime95 - Small FFT's - 10 minutes
Motherboard = Asus P6T Deluxe
Stepping = C0
Vcore Load = 1.300

Idle to Load Delta will vary among systems due to inconsistencies such as Ambient temp, Vcore, clock frequencies, sensor linearity, CPU cooling, heat spreader and heat sinc flatness, thermal compound, computer case cooling, graphics card(s) cooling, and software processes. Excessive background processes running simultaneously may not allow low Idle temps. Low Vcore and stock clock may result in low Idle to Load Delta. High Vcore and overclock may exceed 25c Idle to Load Delta, as shown in the Examples above.

Erroneous BIOS Calibrations from motherboard manufacturers, Factory Calibrations from Intel, and popular temperature monitoring utilities often result in Tcase and Tjunction inaccuracies. Since Intel's Thermal Diode spec is +/-1c, temperatures can still be accurate when SpeedFan is properly Calibrated, which should indicate Core temperatures that are within a few degrees of Real Temp.

Section 11: Offsets

SpeedFan can be configured to correct for inaccurate Tcase (CPU or Temp x) and Tjunction (Core x).

(A) From the Readings tab, click on the Configure button, then click on the Advanced tab, and click on the Chip field, directly under the tabs.

(B) Next, go to SpeedFan's installation Program Group, and click on the Help and HOW-TO Icon. This help file can also be found by searching for the filename speedfan.chm.

(C) Under Contents, click on How to configure, then click on How to set Advanced Options. Read this section, including Other interesting options, with emphasis on Temperature x offset.

(D) If additional help is needed, click on the following link to SpeedFan's homepage, then click on the Support, Articles, Screenshots and F.A.Q. tabs: http://www.almico.com/speedfan.php

When CPU and Core Offsets have been completed, SpeedFan will be accurate. SpeedFan is also extremely useful for observing temperatures and Vcore using the Charts tab, while thermal benchmarking with Prime95 Small FFT's.

Tips:

(A) Tcase may be labeled as CPU, Temp 1, Temp 2 or Temp 3, but is most frequently labeled as Temp 2. Follow Section 8, Note 2 to correctly identify which label corresponds to Tcase.

(B) Tjunction is labeled Core 0, Core 1, etc.

(C) Graphics Processors are labeled Core.

(D) Graphics Cards which display a sensor labeled Ambient, must not be used for measuring room temperature.

(E) SpeedFan flame Icons are alarm limits which can be adjusted to Warm Scale using the Configure button.

(F) SpeedFan Aux 127 is an unassigned input which can be disabled using the Configure button.

(G) Core 0 typically carries heavier loads and higher temps during single threaded gaming and applications, so SpeedFan should be configured to "Show in Tray" Core 0.

Section 12: Overclocking

Intel's Thermal Design Power (TDP) spec can be exceeded by over 50% when CPU frequency is aggressively overclocked, and Vcore is increased to maintain stability. When the default Vcore spec (on the retail box) is increased by just 10%, it becomes difficult to maintain Safe Scale with high-end cooling. As Ambient temperature increases, Vcore and overclock may need to be decreased.

Every processor is unique in it's overclock potential, voltage tolerance, and thermal behavior. If the maximum stable overclock is known at 1.35 Vcore (65nm) or 1.25 Vcore (45nm), then ~ 300 Mhz of additional overclock remains until Safe Scale is exeeded due to increased Vcore. Each increase of 0.05 volts will typically allow a stable increase of ~ 100 Mhz, and will result in a corresponding increase in CPU and Core temperatures of 3 to 4c.

At 1.5 Vcore Max (65nm), or 1.3625 Vcore Max (45nm), or 1.375 Vcore Max (i7) with 100% Workload and 22c Ambient, highly effective CPU cooling and computer case cooling are required to maintain Safe Scale and stability. Ambient and Vcore are the most dominant Variables affecting temperatures.

For Core i7 Overclocking information, please refer to the following link: Intel Core i7-920 Overclocking Guide - http://www.xbitlabs.com/articles/c [...] cking.html

For Core 2 Overclocking information, please refer to the following link: HOWTO: Overclock C2Q (Quads) and C2D (Duals) - A Guide v1.6.1 http://www.tomshardware.com/forum/ [...] uals-guide

Section 13: Heat Score

The following items will enable users to estimate cooling efficiency, identify problem areas, and visualize how environment and system configuration impacts real-world thermal performance. Graphics cards which recirculate heat are a major cause of high temps in gaming rigs, therefore, cards designed with Dual-Slot rear exhaust are preferred.

(A) Ambient:
3 = Over 24c
2 = 22c to 24c
1 = Under 22c

(B) CPU Cooler:
3 = Stock or low-end
2 = Mid-range
1 = High-end

(C) Computer Case Cooling:
3 = Needs improvement
2 = Fair
1 = Excellent

(D) Frequency:
3 = Heavy OC
2 = Moderate OC
1 = Stock or light OC

(E) Graphics Cooling:
3 = Recirculate - dual cards
2 = Recirculate - single card
1 = Rear exhaust - single card / SLI / CrossFire

(F) Hard Drives:
3 = 4 or More
2 = 2 or 3
1 = 1

(G) Vcore: 65nm processors
3 = Over 1.425
2 = 1.35 to 1.425
1 = Under 1.35

(OR)

(G) Vcore: 45nm processors
3 = Over 1.30
2 = 1.225 to 1.30
1 = Under 1.225

Total: (Example System)
(A) = 2
(B) = 2
(C) = 1
(D) = 3
(E) = 1
(F) = 2
(G) = 3
Heat Score = 14

Scale:
17 - 21 = Hot
12 - 16 = Warm
7 - 11 = Safe

Section 14: Recommendations

For information on CPU Coolers, please use the following links:

http://www.anandtech.com/casecooli [...] i=3068&p=4
http://www.frostytech.com/articlev [...] 383&page=5
http://www.madshrimps.be/?action=g [...] rticID=680

Section 15: Troubleshooting

Note: A significant percentage of 45 nanometer processors (E7000, E8000, Q9000 and QX9000 series) are being reported with faulty DTS sensors, where one or all the Cores won't decrease to low Idle temperatures. Offsets between Cores exceeding 10c are also being reported. Sensors can be tested using Real Temp - http://www.techpowerup.com/realtemp/

(A) Vcore will typically droop at least 0.025 volts under full Load.

(B) Offsets between Cores of up to 5c for Quad's and 3c for Duo's are normal.

(C) Any hardware and / or software may misreport Tcase and / or Tjunction temps.

(D) BIOS updates will affect the accuracy of Tcase, but will have no affect on Tjunction.

(E) CPU's manufactured with concave / convex Integrated Heat Spreaders may indicate high Idle to Load Delta.

(F) An improperly seated CPU cooler is the leading cause of abnormally high temperatures.

(G) Ambient and Vcore are the most dominant Variables affecting temperatures.

Section 16: Comments

• This Guide may be frequently revised as new processors and information becomes available.

I hope this helps to bring Core i7 and Core 2 temperatures into perspective. Thank you for reading.

CompuTronix

If you have questions, please post a "New Topic" in the Hardware-Overclocking-CPU Forum.

is there anything like TAT for an AMD cpu?

Hi.
Thanks for the good posts. I understand it. Just wondering.
For a E6400 to idle is 40c and 45c at full load ( from Asus utilities) - is this good?
I have a good heat-sink and I am well within range, but I thought the temps will be lower.
This is the first time I am running a C2D.
Just wondering..
Thanks!

Maybe I need to get better thermal grease.

Question for you Pros. Here's my hardware:

E6400 OC'd to 2.4 with 300 FSB
MSI 965Platinum
Zalman S9500
OCZ DDR800 running at 667, thus OC'd to 750 (is that even a good setting to be at?)
All voltage at default settings

I'm worried and confused about temps. My bios shows 30c, which seems drastically different from the 55-65c that I get with TAT. It doesn't matter if I run my FSB at 266 or 300, I still am 30c in bios, ~55c in TAT at idle, and climbing to as high as 75c under stress. I tried remounting my S9500 with little change. My case is the Antec Superlanboy and seems beyond well ventilated and the room is probably around 65f.

Should I be concerned? Am I basically limited to this mild overclock with my particular E6400? Any suggestions?

Well first thing this morning I remounted the heatsink again. I used a slightly different technique of spreading my silver compound, but I'm still idling in Windows at just a hair under 50c. When I pushed it at 100% stress with TAT one of the cores climbed as high as 77. Just so frustrating when I see that other people with my fan I getting low 40's.

Contact doesn't seem to be obstructed by any other piece, however it can wiggle on the CPU if I push it. Although that seems bad, given the indentions on the bottom of the heatsink and the way these things bolt in I'm not sure if that's not normal. Seems normal. I guess I can contact Zalman and ask for another heatsink.

The only other thing that I can think of is if my silver thermal compound has gone "bad." Or if it's possibly that my sensors are simply making bad readings, or maybe I just fail at Zalman S9500's :? ?

The only thing I can say is THANK YOU! I bookmarked the thread for future reference. This was a necessary post.

Wow, what a day. Besides work and a birthday party for a friend, my copy of Vista arrived in the mail, so naturally I had to dive right in. Bad idea. Several hours later, here's the scoop

MSI's Dual Core Center is showing 25C at the same time that TAT is showing 55C. Huh.

Meh. Flashing my bios AFTER loading vista was a bad idea. Eventually a Boot CD and a Boot Flash Drive put that problem to bed. Upgraded from version 1.2 to 1.3, which from what I hear doesn't affect much. Still, it makes me warm and fuzzy instead knowing it's up to date.

Anyway, given that everything seems to be running stable even at TAT's 55-75C, I'm hoping that the MSI utility is more accurate. Even if I was square in the middle of them I'd be happy.

Thanks a ton for your help CompuTronix, I appreciate it.

Edit: LOL, after just posting this and shutting down explorer I reached down to my computer to turn my fan dial down slightly and the system bluescreened. Perhaps I'm not out of the woods yet. However given that it never did that in XP, I'm hoping it's just Vista.

Actually, my thread doesn't meet the requirements to be a sticky. First off its a review, not a guide. Take a look at most of the stickies and you'll notice that they all help you "do" something, whether that be overclocking or managing the correct Core temps or building a water cooling loop. Segundo, stickies are general in nature, not specified like my reviews. Besides, this deserved it more, especially when I saw many people asking for it. Heck, I considered writing my own guide, but finishing the Thermal Interface review took first place. Thats why I told you to make this into a thread, and why I recommended it.

Besides, one sticky is enough for me for now. I don't want 2 or more that I have to constantly maintain or update. Enjoy it man. You earned it. ^_^

Thank you once again. I still wish to clarify my queries some more, if that's ok with you. I want to get my terms right so I don't confuse myself(and others).

Regarding questions 1 and 2: In short, do you mean that TM2 temperature reading is basically the ordinary Diode reading? And that it also stores the tables for TCaseMax temp(Which is the max temp on the external central point of the IHS that guarantees stable work when TDP is at it's max)

In addition, I understand that TM1=DTS(The digital reading from each core)?

I assume you're referring to the ordinary TM1 and TM2 technologies from Intel, which also cause throttling. If so, I wonder why this is the way it only works on Pentium M based CPUs? TM1/2 were also available in the later models of the Pentium, but in these models only the inaccurate Diode reading is available.
In addition, I have personally experienced and seen cases where TM2 cause throttling, despite having rather low temp reading by the diode. It is not unlikely however, that the real temp was higher, and the sensor was giving an errorenous temp.

In regards to my 3rd question, which should be the max recommended Core Temperature for stable, long overclock, that will not endanger the CPU in the long term(more than the obvious). I have always thought staying below 60 is required, or atleast 65.
I understand that 75 is high, 80 is throttling, and 85 is shutdown temp. However, I'm trying to refer to the recommended general temp for long overclocks.

Thank you again for your explanations.
Best Regards.

It's important to be specific, so without knowing your specs, I would guess that you're running a 965 chipset. The 71c indication you see with TAT, (which is fairly warm), is believable. Assume that the TM2 socket sensor measurement is erroneous by -12c to -15c. It may be possible to correct this condition by flashing your BIOS.

Hope this helps. 8)

Heh... sorry chief:

E6400
MSI 965 Platinum
Zalman 9500

I just flashed to version 1.3 yeserday, with no noticable difference. Not sure what else to try. I have a default clocked (or 300FSB) E6400, silver compound, a very well ventilated case, and the best aircooling heatsink money can buy. Unless that CPU is defective either by non-conduction or bad readings, I can't think of anything else to try.

Thanks a ton for your write up though, I never understood the difference between TM1 and TM2 before.

I wonder if this is something to do with Asus motherboards. I have an E6400 on a P5B-E and the temps from speedfan and Asus probe are consistently 4-5 degrees higher than those from TAT/Core temp. (i.e. TAT is 35C idle, 52C load. Asus probe is 40C idle, 56C load.). Anyone else with Asus mobos have similar results?

Thanks to your explanations, I've got most of it covered.

However, I am trying to to understand all of this more in depth than the scopes of this guide. In addition, there are still several minor issues that seem to contradict your explanations. While I believe your explanations are more accurate(since they are more informative), I wonder if you could refer me to places where I can find more information regarding this?

I do not wish to 'spam' this thread and make it unnecessarily long, so I'd appreciate it if you could refer me to certain places where I can read some more(I've done all the research I can, and I came up with this guide and a few others which doesn't seem thorough enough).

If it is alright by you, it would be great if we can discuss this further.

Best Regards.

CompuTronix, Thank you for the wonderful article. But I'm afraid, that this article tends to contradict many issues we previously discussed.

According to this article, TM2 is the first to invoke throttling. The way it works is by lowering the FID and VID to minimum. When TM2 is not strong enough, the less efficient TM1 takes place simultaneously and tries to help by inserting idle cycles. This article also stresses that TM1 is hardly as efficient as TM2 when it comes to throttling and maintaining normal temperature.

It also seems that TM2 invoked throttling at about 80c core temp, which makes me believe it relies on the DTS sensor, and not on the analog reading from the diode(that isn't A-D converted at any point).

I'm not trying to contradict you or anything, I'm just trying to get to the bottom of this. I would also truly appreciate it if you could link me to a resource which talks about the temperature sensors themselves and how they are related to TM1/TM2. This article mainly spoke about the throttling itself, and not about the temperature reading and sensors.

Best regads,
Guy.

You call this a problem?

I wonder if this is something to do with Asus motherboards. I have an E6400 on a P5B-E and the temps from speedfan and Asus probe are consistently 4-5 degrees higher than those from TAT/Core temp. (i.e. TAT is 35C idle, 52C load. Asus probe is 40C idle, 56C load.). Anyone else with Asus mobos have similar results?

my temps are only change about 4 or 5C from idle to full load with my asus board even with the latest bios i think its 1107. with pc probe/ai suite/bios temperatures range from 47-51 or 52c. with core temp i only have an idle reading of 37-41c.

setup is
ASUS P5B board
CORE 2 DUO e6300
A-DATA 2 X 512 ddr-800
big(maby too big) cooler master cooler w/ AS5

all at stock speed/volt

room temp is about 72 F
MB temp is usualy around 33c
and HDs are usualy between 18-28c

which reading should i trust? the asus board and utilities or coretemp?


brian

The Shin-etsu listed on Newegg is the GXXX version. What we used on the test is X23, a silicon based thermal interface material that can be found at these sites:
http://www.chillblast.com/product.php?productid=16932
http://www.ajigo-store.com/se7783d.html
http://www.crazypc.com/products/50118.html
http://www.watercoolingshop.com/ca [...] &osCsid=78
http://www.specialtech.co.uk/spsho [...] at=0&page=

Hi guys.

New to the forum.
I have a question or 2. I am running an Asus p5bdeluxe, 2x1gb kingston hyperX ddr2 800, thermaltake purepower 560 and just bought an x1950pro.

My prob is that when i got the ram i immediately oc'd to 2.8ghz via 400*7 at vcore of 1.4volts. Stable without any issues except that my machine is much slower. Especially in gaming and 3d benchmarks.

I have been reading and checking post and forums with no luck at all.
Would REALLY appreciate any help.

Thanks

great guide, dont understand some of it, but great guide!

Nice guide thanks for the link and the effort! I can confirm TAT is reading roughly 20C Higher on Vista and its not just wishful thinking! For confirmation I used Everest Ultimate and Speenfan Both showed the same temp which was on average 20C lower than tat and occassionally 15C lower no more.

I'm having a TCase/Tjunction issue concerning TCase being reported higher than the TJunction. First, I'd like to determine which temps are being erroneously identifed. So, here's my situation:

Tcase = 37 (32 in BIOS upon restart) & 55 (up to 62 with TAT)
Tjunction = 32 & 50-55

Ambient = 20
Chipset = Nvidia 680i
C2D = e6400
CPU Cooler = Arctic Cooler Freezer Pro 7/Ceramique
Frequency = OCed to 3.2 (linked/synced with 1600QDR)
Load = Orthos/TAT/OCCT/3DMark2006
Motherboard = EVGA
Vcore = 1.25

I'm wondering, of course, why my Tcase is higher than my Tjunction. Is my TJunction more likely to be being reported incorrectly than my TCase? That is, is it likely that my Tcase is correct, meaning my TJunction Idle/Load values are really more like 47/70-75. The Tjunction values reported above are consistent across TAT, CoreTemp, and SpeedFan. Any guidance would be much appreciated.

I get similar results as you... and I understand it to be that TAT is measuring directly from two diodes within the chip, and the mobo's sensor is positioned as to the heat is already transferring and losing energy before it is read on mobo sensors.
Also, the TAT program was programed for Meriom mobile chips, and states it is only intended to be used on like processors.
So it could be a design difference due to different voltages being read from C2D's diodes, within the formula to calculate the thermal coefficients which are causing such discrepancies.

Thanks OP.

when i try and run TAT i get this error..

"Error enumerating On Demand Clock Modulation support.
Terminating Tool."

:?