Pulled from Toms hardware...
Core 2 Quad and Duo Temperature Guide: Update 07 May 08
Preface:
The purpose of this Guide is to provide users with an understanding of thermal relationships, so that C2Q and C2D computers can be uniformly tested, accurately calibrated, and properly monitored. This Guide supports 65 and 45 nanometer Core 2 desktop processors. All temperatures in this Guide are referenced to Standard Ambient 22c. As users will be working in BIOS, it is recommended that this Guide be printed for quick reference.
Scope:
This Guide applies primarily to overclocked systems, since temperatures on stock systems are rarely an issue. This Guide is intended for intermediate level enthusiasts. This Guide requires basic familiarity with computer terminology, BIOS menus and SpeedFan, but does not require knowledge of unnecessarily diverse or complex technical details. Certain strict definitions have therefore been relaxed to simplify concepts and enhance comprehension.
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
Intel provides separate thermal specifications for 2 different sensor types; a CPU Case (not computer case) Thermal Diode located within the CPU die between the Cores, and Digital Thermal Sensors located within each Core. The Case Thermal Diode measures Tcase (Temperature Case), which is CPU temp, and the Digital Thermal Sensors measure Tjunction (Temperature Junction), which is Core temp. Since these sensors measure 2 distinct thermal levels, there is a constant temperature gradient between them, which is Tcase to Junction Delta. C2Q`s have 1 Tcase and 4 Junction sensors, while C2D`s have 1 Tcase and 2 Junction sensors.
Intel does not provide documentation comparing Tcase and Junction specifications. Consequently, there is much confusion among users regarding temperature monitoring utilities, test methods, Calibrations and Offsets, so Results can be difficult to decipher and compare. Therefore, when discussing temperatures, it is very important to be clear. Also, when listing Idle & Load test Results, it is necessary to list the Variables as shown below:
Results
Tcase = Idle & Load
Tjunction = Idle & Load
Variables
Ambient = Room Temp
Chipset = Model
C2Q / C2D = Model
CPU Cooler = Model
Frequency = CPU Clock
Load = Test Program
Motherboard = Model
Stepping = Revision
Vcore = CPU Voltage
Section 2: Specifications
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 Vcore, Stepping, Thermal Design Power and Maximum Case 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:
Ambient Temperature = 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 lab tests only, IHS temperature is replicated using a CPU Case Thermal Diode integrated between the Cores. Maximum Case Temperature is determined by Spec#. The CPU Case Thermal Diode is how Tcase is measured, and is the CPU temperature displayed in BIOS and the software utility SpeedFan.
(**) The second part of the spec refers to mobile processors without Integrated Heat Spreaders (IHS). Although desktop CPU`s have an IHS, both variants measure the hot spots within each Core using Digital Thermal Sensors (DTS). Maximum Junction Temperatures are determined by factory Calibrations. The Digital Thermal Sensors are how Tjunction is measured, and are the Core temperatures displayed in the software utility SpeedFan.
Section 4: Thermal Flow
Heat originates within the Cores, where Tjunction sensors are located within the hot spots of each Core. Heat dissipates from the bottom of the Cores through the CPU Case, which creates a thermal gradient toward the center of the Die, where the Tcase sensor is located. Heat then dissipates through the socket and motherboard to air inside the computer case. Heat also dissipates from the top of the Cores through the Integrated Heat Spreader and CPU cooler to air inside the computer case. Safe and sustainable temperatures are determined by CPU cooling efficiency, computer case cooling efficiency, Ambient temperature, Vcore, clock speed and Load.
* Tjunction is always higher than Tcase.
* Tcase is always higher than Ambient.
Section 5: Findings
(A) Tcase is acquired on the CPU Die from the CPU Case Thermal Diode as an analog level, which is converted to a digital value by the super I/O chip on the motherboard. The digital value is BIOS Calibrated and displayed by temperature software. BIOS Calibration affects the accuracy of Tcase, or CPU temperature.
(B) Tjunction is acquired within the Cores from Thermal Diodes as analog levels, which are converted to digital values by the Digital Thermal Sensors (DTS) within each Core. The digital values are Factory Calibrated and displayed by temperature software. Factory Calibration affects the accuracy of Tjunction, or Core temperatures.
(C) Tcase and Tjunction are both acquired from Thermal Diodes. Tcase and Tjunction analog to digital (A to D) conversions are executed by separate devices in different locations. BIOS Calibrations from motherboard manufacturers, Factory Calibrations from Intel, and popular temperature utilities are frequently inaccurate.
(D) Intel shows Maximum Case Temperature (Tcase Max) in the Processor Spec Finder, which is the only temperature that Intel supports on Core 2 desktop processors. Ambient to Tcase Delta has known Offsets which vary with power dissipation and cooler efficiency, and can be Calibrated at Idle using a standardized Test Setup.
* Ambient can be used to Calibrate Tcase at Idle.
(E) Intel does not provide documentation for Maximum Junction Temperature (Tjunction Max) on Core 2 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, and not an absolute temperature.
(F) Tjunction Max must be known to calculate absolute Core temperature, which is Tjunction. Without this information, popular temperature utilities may incorrectly estimate Tjunction Max, which results in excessive Core temperatures and inconsistent Tcase to Tjunction Delta among C2Q and C2D variants.
(G) Existing test data from several Intel papers - http://eda-publishing.imag.fr/spip/IMG/pdf/TMI23.pdf - as well as numerous independent sources show Tcase to Tjunction Delta has a known Offset which is 5c, and can be Calibrated at Load using a standardized Test Setup.
* Tcase can be used to Calibrate Tjunction at 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 Delta between Tcase and Tjunction. Although the 5c Delta 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 Delta to indicate as low as 3c at Idle, while high Vcore and overclock may cause the Delta to reach 7c at Load.
If temperatures increase beyond Hot Scale, then ~ 5c 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 increase further to Tjunction Max, then Shutdown occurs. Since Tcase indicates CPU Die 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.
Scale 1: Duo
E7200: Tcase Max 74c, Stepping M0
E4700: Tcase Max 73c, Stepping G0
E4x00: Tcase Max 73c, Stepping M0
E2xx0: Tcase Max 73c, Stepping M0
E8x00: Tcase Max 72c, Stepping C0
E8x90: Tcase Max 72c, Stepping C0
E6x50: Tcase Max 72c, Stepping G0
E6540: Tcase Max 72c, Stepping G0
-Tcase/Tjunction-
--70--/--75--75-- Hot
--65--/--70--70-- Warm
--60--/--65--65-- Safe
--25--/--30--30-- Cool
Scale 2: Quad
Q9x50: Tcase Max 71c, Stepping C1
Q9300: Tcase Max 71c, Stepping M1
Q6x00: Tcase Max 71c, Stepping G0
-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 3: Quad
QX6x50: Tcase Max 65c, Stepping G0
QX6800: Tcase Max 65c, Stepping G0
QX6700: Tcase Max 65c, Stepping B3
QX9650: Tcase Max 64c, Stepping C0
QX9775: Tcase Max 63c, Stepping C0
-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 4: Quad
Q6600: Tcase Max 62c, Stepping B3
-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 5: Duo
E6x00: Tcase Max 61c, Stepping L2
E4x00: Tcase Max 61c, Stepping L2
E21x0: Tcase Max 61c, Stepping L2
X6800: Tcase Max 60c, Stepping B2
E6x00: Tcase Max 60c, Stepping B2
E6x20: Tcase Max 60c, Stepping B2
-Tcase/Tjunction-
--60--/--65--65-- Hot
--55--/--60--60-- Warm
--50--/--55--55-- Safe
--25--/--30--30-- Cool
Scale 6: Quad
QX6800: Tcase Max 55c, Stepping B3
-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 Delta 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 1.3625 volts on 45nm processors.
(G) Vcore Load should not exceed 1.5 volts on 65nm processors.
(H) Tjunction average should Idle at least 3c higher than Tcase.
(I) Tjunction Idle and Load Results are average temperatures.
(J) Idle to Load Delta may exceed 25c when overclocked.
Section 8: Tools
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 1.45: http://www.cpuid.com/cpuz.php
* Prime95 25.6: http://www.majorgeeks.com/Prime95_d4363.html
* SpeedFan 4.34 displays Tcase and Tjunction: 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 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.
Note 3: TAT - The software utility (TAT) Thermal Analysis Tool at maximum settings will simulate 100% Thermal Load, which would equal Prime95 Small FFT`s at 114% Workload ~ 5c hotter. This provides the most extreme testing available for CPU and system cooling efficiency. Since TAT is coded to measure Notebook temps, it identifies a C2D as Pentium M. As Notebooks have no Integrated Heat Spreader, thermal scaling differs from desktop CPU`s, so TAT indicates ~ 2c lower, and depending on Variables, temps may be Offset by more than 15c. It is therefore recommended that TAT be used for extreme thermal testing only, and temps regarded as unreliable.
Section 9: Calibrations
Prerequisites:
(A) CPU cooler correctly installed.
(B) Record or photo or Save Profile all BIOS settings for quick restore when Calibrations are complete.
(C) Test Setup: Standardized configuration for maximum cooling at Auto Vcore, Frequency and Multiplier.
Computer Case Covers = Removed
Computer Case Fans = Manual 100% RPM
Connectivity Status = Offline
CPU Fan = Manual 100% RPM
CPU Frequency = Auto
CPU Internal Thermal Control = Enabled
Enhanced C1 Control (C1E) = Enabled
Memory Frequency = Auto
PECI (If Equipped) = Enabled
Speedstep (EIST) = Enabled
Vcore = Auto
Vdimm = Auto
Windows Programs = Closed
Note 1: PECI (Platform Environmental Control Interface) is a BIOS feature on some (not all) recent motherboards which determines the method by which chipsets interpret and manage CPU temperature. When enabled, thermal accuracy is enhanced, and if disabled, temperatures are typically inverted, where Tcase is higher than Tjunction.
Note 2: It is preferred that Idle and Load tests be conducted as close to 22c Standard Ambient as possible to allow for a normal temperature ceiling, and to maintain environmental consistency for more uniform comparisons among C2Q / C2D variants and system platforms.
The following two part procedure is designed to achieve two objectives:
* Provide minimum Ambient to Tcase Delta for accurate Tcase Calibration at Idle.
* Provide maximum Tcase to Tjunction Delta for accurate Tjunction Calibration at Load.
Part 1: Calibration - Tcase Idle (Uses maximum cooling at minimum Vcore, Frequency and Multiplier)
(A) Measure Ambient near computer case air intake, clear of warm exhaust. A trusted analog or digital thermometer will suffice.
(B) Boot into Windows. Close all programs, background processes, 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 2%. 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.
(D) Tcase should indicate Ambient + Z, which is the Delta based on Idle power dissipation and CPU cooler efficiency. Check the links in Section 14 to determine CPU cooler efficiency. Since there are multiple processor and cooler combinations, use the following table to choose the Delta which most closely matches the hardware configuration:
X = 1 . . . Idle power: low (E2xxx, E7xxx) . . . . . . . . . . Y = 1 . . . Cooler efficiency: high-end
X = 2 . . . Idle power: low-average (E4xxx, E8xxx) . . . Y = 2 . . . Cooler efficiency: high mid-range
X = 3 . . . Idle power: average (E6xxx) . . . . . . . . . . . . Y = 3 . . . Cooler efficiency: mid-range
X = 4 . . . Idle power: high-average (Q9xxx) . . . . . . . . Y = 4 . . . Cooler efficiency: low mid-range
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Y = 5 . . . Cooler efficiency: low-end
X = 6 . . . Idle power: high (Q6xxx) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Y = 9 . . . Cooler efficiency: stock Intel
(X + Y) / 2 = Z
Z = Ambient to Tcase Delta.
Example 1: Duo
Idle power dissipation: E2xxx, X = 1.
Cooler efficiency: Thermalright Ultra 120 Extreme, Y = 1.
(1 + 1) / 2 = Ambient to Tcase Delta 1c.
Example 2: Duo
Idle power dissipation: E6xxx, X = 4.
Cooler efficiency: Arctic Cooling Freezer 7 Pro, Y = 3.
(4 + 3) / 2 = Ambient to Tcase Delta 3.5c, rounded off to 4c.
Example 3: Quad
Idle power dissipation: Q6xxx, X = 6.
Cooler efficiency: stock Intel, Y = 9.
(6 + 9) / 2 = Ambient to Tcase Delta 7.5c, rounded off to 8c.
(E) If Offset correction is required, Configure SpeedFan as shown in Section 11.
Part 2: Calibration - Tjunction Load (Uses maximum cooling at stock Vcore, Frequency and Multiplier)
(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 average.
(B) Tjunction average should indicate Tcase + 5c. A tolerance of +/- 2 allows for deviations between highest and lowest Cores.
(C) If Offset correction is required, Configure SpeedFan as shown in Section 11. Enter identical correction values to each Core. For Quad Cores, if an individual Core is still out of tolerance, then enter only enough additional Offset correction to reach tolerance. Do not set individual Cores to Tjunction average.
(D) Stop Prime95, then allow the system to Idle for 10 minutes. Tjunction average should Idle at least 3c higher than Tcase. Readjust individual Cores which indicate excessively low temps, then repeat items (A) thru (D).
(E) Repeat Item (A) and allow Prime95 to run past 10 minutes while reinstalling covers. If temperatures increase, then computer case cooling should be improved.
(F) 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 Tcase to Tjunction Delta average is 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 Delta average to indicate as low as 3c at Idle on an E2xxx, while a heavily overclocked Q6xxx with high Vcore may reach a Tcase to Tjunction Delta average of 7c at Load.
If temperatures are allowed to increase beyond Hot Scale, then ~ 5c below Tjunction Max Throttling is activated. If Core temperatures increase further to 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 Delta shows 7c 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: Quad
Tcase = 26c Idle, 60c Load (SpeedFan: CPU or Temp x)
Tjunction average = 30c Idle, 67c Load (SpeedFan: Core x)
Ambient = 22c
Chipset = P35
CPU = Q6600
CPU Cooler= Thermalright Ultra 120 Extreme
Frequency = 3.6 Ghz
Load = Prime95 - Small FFT`s - 10 minutes
Motherboard = Asus P5K Deluxe
Stepping = G0
Vcore Load = 1.45
Example 2: Duo
Tcase = 25c Idle, 60c Load (SpeedFan: CPU or Temp x)
Tjunction average Core = 29c Idle, 67c Load (SpeedFan: Core x)
Ambient = 22c
Chipset = X38
CPU = E8400
CPU Cooler= Arctic Cooling Freezer 7 Pro
Frequency = 4.0 Ghz
Load = Prime95 - Small FFT`s - 10 minutes
Motherboard = Asus P5E
Stepping = C0
Vcore Load = 1.325
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 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 quite accurate when properly Calibrated.
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 F.A.Q. tab: 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.
Core 2 Quad and Duo Temperature Guide: Update 07 May 08
Preface:
The purpose of this Guide is to provide users with an understanding of thermal relationships, so that C2Q and C2D computers can be uniformly tested, accurately calibrated, and properly monitored. This Guide supports 65 and 45 nanometer Core 2 desktop processors. All temperatures in this Guide are referenced to Standard Ambient 22c. As users will be working in BIOS, it is recommended that this Guide be printed for quick reference.
Scope:
This Guide applies primarily to overclocked systems, since temperatures on stock systems are rarely an issue. This Guide is intended for intermediate level enthusiasts. This Guide requires basic familiarity with computer terminology, BIOS menus and SpeedFan, but does not require knowledge of unnecessarily diverse or complex technical details. Certain strict definitions have therefore been relaxed to simplify concepts and enhance comprehension.
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
Intel provides separate thermal specifications for 2 different sensor types; a CPU Case (not computer case) Thermal Diode located within the CPU die between the Cores, and Digital Thermal Sensors located within each Core. The Case Thermal Diode measures Tcase (Temperature Case), which is CPU temp, and the Digital Thermal Sensors measure Tjunction (Temperature Junction), which is Core temp. Since these sensors measure 2 distinct thermal levels, there is a constant temperature gradient between them, which is Tcase to Junction Delta. C2Q`s have 1 Tcase and 4 Junction sensors, while C2D`s have 1 Tcase and 2 Junction sensors.
Intel does not provide documentation comparing Tcase and Junction specifications. Consequently, there is much confusion among users regarding temperature monitoring utilities, test methods, Calibrations and Offsets, so Results can be difficult to decipher and compare. Therefore, when discussing temperatures, it is very important to be clear. Also, when listing Idle & Load test Results, it is necessary to list the Variables as shown below:
Results
Tcase = Idle & Load
Tjunction = Idle & Load
Variables
Ambient = Room Temp
Chipset = Model
C2Q / C2D = Model
CPU Cooler = Model
Frequency = CPU Clock
Load = Test Program
Motherboard = Model
Stepping = Revision
Vcore = CPU Voltage
Section 2: Specifications
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 Vcore, Stepping, Thermal Design Power and Maximum Case 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:
Ambient Temperature = 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 lab tests only, IHS temperature is replicated using a CPU Case Thermal Diode integrated between the Cores. Maximum Case Temperature is determined by Spec#. The CPU Case Thermal Diode is how Tcase is measured, and is the CPU temperature displayed in BIOS and the software utility SpeedFan.
(**) The second part of the spec refers to mobile processors without Integrated Heat Spreaders (IHS). Although desktop CPU`s have an IHS, both variants measure the hot spots within each Core using Digital Thermal Sensors (DTS). Maximum Junction Temperatures are determined by factory Calibrations. The Digital Thermal Sensors are how Tjunction is measured, and are the Core temperatures displayed in the software utility SpeedFan.
Section 4: Thermal Flow
Heat originates within the Cores, where Tjunction sensors are located within the hot spots of each Core. Heat dissipates from the bottom of the Cores through the CPU Case, which creates a thermal gradient toward the center of the Die, where the Tcase sensor is located. Heat then dissipates through the socket and motherboard to air inside the computer case. Heat also dissipates from the top of the Cores through the Integrated Heat Spreader and CPU cooler to air inside the computer case. Safe and sustainable temperatures are determined by CPU cooling efficiency, computer case cooling efficiency, Ambient temperature, Vcore, clock speed and Load.
* Tjunction is always higher than Tcase.
* Tcase is always higher than Ambient.
Section 5: Findings
(A) Tcase is acquired on the CPU Die from the CPU Case Thermal Diode as an analog level, which is converted to a digital value by the super I/O chip on the motherboard. The digital value is BIOS Calibrated and displayed by temperature software. BIOS Calibration affects the accuracy of Tcase, or CPU temperature.
(B) Tjunction is acquired within the Cores from Thermal Diodes as analog levels, which are converted to digital values by the Digital Thermal Sensors (DTS) within each Core. The digital values are Factory Calibrated and displayed by temperature software. Factory Calibration affects the accuracy of Tjunction, or Core temperatures.
(C) Tcase and Tjunction are both acquired from Thermal Diodes. Tcase and Tjunction analog to digital (A to D) conversions are executed by separate devices in different locations. BIOS Calibrations from motherboard manufacturers, Factory Calibrations from Intel, and popular temperature utilities are frequently inaccurate.
(D) Intel shows Maximum Case Temperature (Tcase Max) in the Processor Spec Finder, which is the only temperature that Intel supports on Core 2 desktop processors. Ambient to Tcase Delta has known Offsets which vary with power dissipation and cooler efficiency, and can be Calibrated at Idle using a standardized Test Setup.
* Ambient can be used to Calibrate Tcase at Idle.
(E) Intel does not provide documentation for Maximum Junction Temperature (Tjunction Max) on Core 2 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, and not an absolute temperature.
(F) Tjunction Max must be known to calculate absolute Core temperature, which is Tjunction. Without this information, popular temperature utilities may incorrectly estimate Tjunction Max, which results in excessive Core temperatures and inconsistent Tcase to Tjunction Delta among C2Q and C2D variants.
(G) Existing test data from several Intel papers - http://eda-publishing.imag.fr/spip/IMG/pdf/TMI23.pdf - as well as numerous independent sources show Tcase to Tjunction Delta has a known Offset which is 5c, and can be Calibrated at Load using a standardized Test Setup.
* Tcase can be used to Calibrate Tjunction at 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 Delta between Tcase and Tjunction. Although the 5c Delta 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 Delta to indicate as low as 3c at Idle, while high Vcore and overclock may cause the Delta to reach 7c at Load.
If temperatures increase beyond Hot Scale, then ~ 5c 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 increase further to Tjunction Max, then Shutdown occurs. Since Tcase indicates CPU Die 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.
Scale 1: Duo
E7200: Tcase Max 74c, Stepping M0
E4700: Tcase Max 73c, Stepping G0
E4x00: Tcase Max 73c, Stepping M0
E2xx0: Tcase Max 73c, Stepping M0
E8x00: Tcase Max 72c, Stepping C0
E8x90: Tcase Max 72c, Stepping C0
E6x50: Tcase Max 72c, Stepping G0
E6540: Tcase Max 72c, Stepping G0
-Tcase/Tjunction-
--70--/--75--75-- Hot
--65--/--70--70-- Warm
--60--/--65--65-- Safe
--25--/--30--30-- Cool
Scale 2: Quad
Q9x50: Tcase Max 71c, Stepping C1
Q9300: Tcase Max 71c, Stepping M1
Q6x00: Tcase Max 71c, Stepping G0
-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 3: Quad
QX6x50: Tcase Max 65c, Stepping G0
QX6800: Tcase Max 65c, Stepping G0
QX6700: Tcase Max 65c, Stepping B3
QX9650: Tcase Max 64c, Stepping C0
QX9775: Tcase Max 63c, Stepping C0
-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 4: Quad
Q6600: Tcase Max 62c, Stepping B3
-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 5: Duo
E6x00: Tcase Max 61c, Stepping L2
E4x00: Tcase Max 61c, Stepping L2
E21x0: Tcase Max 61c, Stepping L2
X6800: Tcase Max 60c, Stepping B2
E6x00: Tcase Max 60c, Stepping B2
E6x20: Tcase Max 60c, Stepping B2
-Tcase/Tjunction-
--60--/--65--65-- Hot
--55--/--60--60-- Warm
--50--/--55--55-- Safe
--25--/--30--30-- Cool
Scale 6: Quad
QX6800: Tcase Max 55c, Stepping B3
-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 Delta 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 1.3625 volts on 45nm processors.
(G) Vcore Load should not exceed 1.5 volts on 65nm processors.
(H) Tjunction average should Idle at least 3c higher than Tcase.
(I) Tjunction Idle and Load Results are average temperatures.
(J) Idle to Load Delta may exceed 25c when overclocked.
Section 8: Tools
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 1.45: http://www.cpuid.com/cpuz.php
* Prime95 25.6: http://www.majorgeeks.com/Prime95_d4363.html
* SpeedFan 4.34 displays Tcase and Tjunction: 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 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.
Note 3: TAT - The software utility (TAT) Thermal Analysis Tool at maximum settings will simulate 100% Thermal Load, which would equal Prime95 Small FFT`s at 114% Workload ~ 5c hotter. This provides the most extreme testing available for CPU and system cooling efficiency. Since TAT is coded to measure Notebook temps, it identifies a C2D as Pentium M. As Notebooks have no Integrated Heat Spreader, thermal scaling differs from desktop CPU`s, so TAT indicates ~ 2c lower, and depending on Variables, temps may be Offset by more than 15c. It is therefore recommended that TAT be used for extreme thermal testing only, and temps regarded as unreliable.
Section 9: Calibrations
Prerequisites:
(A) CPU cooler correctly installed.
(B) Record or photo or Save Profile all BIOS settings for quick restore when Calibrations are complete.
(C) Test Setup: Standardized configuration for maximum cooling at Auto Vcore, Frequency and Multiplier.
Computer Case Covers = Removed
Computer Case Fans = Manual 100% RPM
Connectivity Status = Offline
CPU Fan = Manual 100% RPM
CPU Frequency = Auto
CPU Internal Thermal Control = Enabled
Enhanced C1 Control (C1E) = Enabled
Memory Frequency = Auto
PECI (If Equipped) = Enabled
Speedstep (EIST) = Enabled
Vcore = Auto
Vdimm = Auto
Windows Programs = Closed
Note 1: PECI (Platform Environmental Control Interface) is a BIOS feature on some (not all) recent motherboards which determines the method by which chipsets interpret and manage CPU temperature. When enabled, thermal accuracy is enhanced, and if disabled, temperatures are typically inverted, where Tcase is higher than Tjunction.
Note 2: It is preferred that Idle and Load tests be conducted as close to 22c Standard Ambient as possible to allow for a normal temperature ceiling, and to maintain environmental consistency for more uniform comparisons among C2Q / C2D variants and system platforms.
The following two part procedure is designed to achieve two objectives:
* Provide minimum Ambient to Tcase Delta for accurate Tcase Calibration at Idle.
* Provide maximum Tcase to Tjunction Delta for accurate Tjunction Calibration at Load.
Part 1: Calibration - Tcase Idle (Uses maximum cooling at minimum Vcore, Frequency and Multiplier)
(A) Measure Ambient near computer case air intake, clear of warm exhaust. A trusted analog or digital thermometer will suffice.
(B) Boot into Windows. Close all programs, background processes, 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 2%. 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.
(D) Tcase should indicate Ambient + Z, which is the Delta based on Idle power dissipation and CPU cooler efficiency. Check the links in Section 14 to determine CPU cooler efficiency. Since there are multiple processor and cooler combinations, use the following table to choose the Delta which most closely matches the hardware configuration:
X = 1 . . . Idle power: low (E2xxx, E7xxx) . . . . . . . . . . Y = 1 . . . Cooler efficiency: high-end
X = 2 . . . Idle power: low-average (E4xxx, E8xxx) . . . Y = 2 . . . Cooler efficiency: high mid-range
X = 3 . . . Idle power: average (E6xxx) . . . . . . . . . . . . Y = 3 . . . Cooler efficiency: mid-range
X = 4 . . . Idle power: high-average (Q9xxx) . . . . . . . . Y = 4 . . . Cooler efficiency: low mid-range
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Y = 5 . . . Cooler efficiency: low-end
X = 6 . . . Idle power: high (Q6xxx) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Y = 9 . . . Cooler efficiency: stock Intel
(X + Y) / 2 = Z
Z = Ambient to Tcase Delta.
Example 1: Duo
Idle power dissipation: E2xxx, X = 1.
Cooler efficiency: Thermalright Ultra 120 Extreme, Y = 1.
(1 + 1) / 2 = Ambient to Tcase Delta 1c.
Example 2: Duo
Idle power dissipation: E6xxx, X = 4.
Cooler efficiency: Arctic Cooling Freezer 7 Pro, Y = 3.
(4 + 3) / 2 = Ambient to Tcase Delta 3.5c, rounded off to 4c.
Example 3: Quad
Idle power dissipation: Q6xxx, X = 6.
Cooler efficiency: stock Intel, Y = 9.
(6 + 9) / 2 = Ambient to Tcase Delta 7.5c, rounded off to 8c.
(E) If Offset correction is required, Configure SpeedFan as shown in Section 11.
Part 2: Calibration - Tjunction Load (Uses maximum cooling at stock Vcore, Frequency and Multiplier)
(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 average.
(B) Tjunction average should indicate Tcase + 5c. A tolerance of +/- 2 allows for deviations between highest and lowest Cores.
(C) If Offset correction is required, Configure SpeedFan as shown in Section 11. Enter identical correction values to each Core. For Quad Cores, if an individual Core is still out of tolerance, then enter only enough additional Offset correction to reach tolerance. Do not set individual Cores to Tjunction average.
(D) Stop Prime95, then allow the system to Idle for 10 minutes. Tjunction average should Idle at least 3c higher than Tcase. Readjust individual Cores which indicate excessively low temps, then repeat items (A) thru (D).
(E) Repeat Item (A) and allow Prime95 to run past 10 minutes while reinstalling covers. If temperatures increase, then computer case cooling should be improved.
(F) 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 Tcase to Tjunction Delta average is 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 Delta average to indicate as low as 3c at Idle on an E2xxx, while a heavily overclocked Q6xxx with high Vcore may reach a Tcase to Tjunction Delta average of 7c at Load.
If temperatures are allowed to increase beyond Hot Scale, then ~ 5c below Tjunction Max Throttling is activated. If Core temperatures increase further to 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 Delta shows 7c 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: Quad
Tcase = 26c Idle, 60c Load (SpeedFan: CPU or Temp x)
Tjunction average = 30c Idle, 67c Load (SpeedFan: Core x)
Ambient = 22c
Chipset = P35
CPU = Q6600
CPU Cooler= Thermalright Ultra 120 Extreme
Frequency = 3.6 Ghz
Load = Prime95 - Small FFT`s - 10 minutes
Motherboard = Asus P5K Deluxe
Stepping = G0
Vcore Load = 1.45
Example 2: Duo
Tcase = 25c Idle, 60c Load (SpeedFan: CPU or Temp x)
Tjunction average Core = 29c Idle, 67c Load (SpeedFan: Core x)
Ambient = 22c
Chipset = X38
CPU = E8400
CPU Cooler= Arctic Cooling Freezer 7 Pro
Frequency = 4.0 Ghz
Load = Prime95 - Small FFT`s - 10 minutes
Motherboard = Asus P5E
Stepping = C0
Vcore Load = 1.325
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 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 quite accurate when properly Calibrated.
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 F.A.Q. tab: 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.
