64-bit Intel® Xeon™ Processor with 2MB L2 Cache Thermal/Mechanical Design Guidelines February 2005 Order Number: 306250-001
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Contents 1 Introduction......................................................................................................................... 7 1.1 1.2 1.3 1.4 2 Objective ..............................................................................................................................7 Scope ...................................................................................................................................7 References.........................................................
E.1 Thermal E.1.1 E.1.2 E.1.3 E.1.4 E.1.5 E.1.6 E.1.7 E.1.8 E.1.9 Management Logic and Thermal Monitor Feature .............................................. 69 Processor Power Dissipation .............................................................................. 69 Thermal Monitor Implementation ........................................................................ 69 Operation and Configuration............................................................................... 71 Thermal Monitor 2.....
A-14 A-15 A-16 A-17 A-18 A-19 A-20 C-1 C-2 E-1 E-2 E-3 E-4 Components (Sheet 6 of 6)................................................................................................52 1U CEK Heatsink (Sheet 1 of 4) ........................................................................................53 1U CEK Heatsink (Sheet 2 of 4) ........................................................................................54 1U CEK Heatsink (Sheet 3 of 4) .....................................................
Revision History Document Number Revision Number 306250 -001 Description Initial release of the document.
1 Introduction 1.1 Objective To describe the reference thermal solution and design parameters required for 64-bit Intel® Xeon™ Processor with 2MB L2 Cache. It is also the intent of this document to comprehend and demonstrate the processor cooling solution features and requirements. Furthermore, this document provides an understanding of the processor thermal characteristics, and discusses guidelines for meeting the thermal requirements imposed on the entire life of the processor.
Introduction Table 1-1. Reference DocumentsIntroduction.fm (Sheet 2 of 2) 64-bit Intel® Xeon™ Processor with 2MB L2 Cache Thermal Models (in Flotherm* and Icepak*) Available electronically 64-bit Intel® Xeon™ Processor with 2MB L2 Cache Cooling Solution Thermal Models (in Flotherm* and Icepak* format) Available electronically Thin Electronics Bay Specification (A Server System Infrastructure (SSI) Specification for Rack Optimized Servers http://www.ssiforum.
Introduction Table 1-2. Terms and Descriptions (Sheet 2 of 2) Thermal Profile Line that defines case temperature specification of a processor at a given power level. TIM Thermal Interface Material: The thermally conductive compound between the heatsink and the processor case. This material fills the air gaps and voids, and enhances the transfer of the heat from the processor case to the heatsink. TLA The measured ambient temperature locally surrounding the processor.
Introduction 10 64-bit Intel® Xeon™ Processor with 2MB L2 Cache Thermal/Mechanical Design Guidelines
2 Thermal/Mechanical Reference Design 2.1 Mechanical Requirements The mechanical performance of the processor cooling solution must satisfy the requirements described in this section. 2.1.1 Processor Mechanical Parameters Table 2-1. Processor Mechanical Parameters Parameter Minimum Maximum Unit Volumetric Requirements and Keepouts Refer to drawings in Appendix A Heatsink Mass Static Compressive Load Dynamic Compressive Load 1000 g 2.
Thermal/Mechanical Reference Design 2.1.2 64-bit Intel® Xeon™ Processor with 2MB L2 Cache Package The 64-bit Intel Xeon Processor with 2MB L2 Cache processor is packaged using the flip-chip micro pin grid array 4 (FC-mPGA4) package technology. Please refer to the 64-bit Intel® Xeon™ Processor with 2MB L2 Cache Datasheet for detailed mechanical specifications.
Thermal/Mechanical Reference Design The package includes an integrated heat spreader (IHS). The IHS transfers the non-uniform heat from the die to the top of the IHS, out of which the heat flux is more uniform and spread over a larger surface area (not the entire IHS area). This allows more efficient heat transfer out of the package to an attached cooling device. The IHS is designed to be the interface for contacting a heatsink.
Thermal/Mechanical Reference Design The Intel reference design for 64-bit Intel Xeon Processor with 2MB L2 Cache is using such a heatsink attachment scheme. Refer to Section 2.4 for further information regarding the Intel reference mechanical solution. 2.2 Thermal Requirements The operating thermal limits of the processor are defined by the Thermal Profile.
Thermal/Mechanical Reference Design Figure 2-2. Thermal Profile Diagram The higher end point of the Thermal Profile represents the processor’s TDP and the associated maximum case temperature (TCASEMAX). The lower end point of the Thermal Profile represents the power value (PCONTROL_BASE) and the associated case temperature (TCASEMAX@ PCONTROL_BASE) for the lowest possible theoretical value of TCONTROL (see Section 2.2.2).
Thermal/Mechanical Reference Design 2.2.2 TCONTROL Definition TCONTROL is a temperature specification based on a temperature reading from the processor’s thermal diode. TCONTROL defines the lower end of the Thermal Profile line for a given processor, and it can be described as a trigger point for fan speed control implementation. The value for TCONTROL is calibrated in manufacturing and configured for each processor individually.
Thermal/Mechanical Reference Design Profile, but the diode temperature must remain at or below TCONTROL. In other words, there is no TCASE specification for the processor at power levels less than Pcontrol. The thermal solution for the processor must be able to keep the processor’s TCASE at or below the TCASE values defined by the Thermal Profile between the TCASEMAX @TCONTROL and TCASEMAX points at the corresponding power levels. Refer to Section 2.3.
Thermal/Mechanical Reference Design the Thermal Monitor features. Measurable performance loss is defined to be any degradation in the processor’s performance greater than 1.5%. The 1.5% number is chosen as the baseline since the run-to-run variation in a given performance benchmark is typically between 1 - 2%.
Thermal/Mechanical Reference Design Table 2-2 describes thermal performance targets for the processor cooling solution enabled by Intel. Table 2-2. Intel Reference Heatsink Performance Targets for the 64-bit Intel® Xeon™ Processor with 2MB L2 Cache 2.2.5 Thermal Solution Type Target Thermal Profile TLA Assumption (°C) TDP (W) Thermal Performance Target, Ψca (Mean + 3σ) (°C/W) 2U+ Form Factor Thermal Profile A 40°C 110 0.293 1U Form Factor Thermal Profile B 40°C 110 0.
Thermal/Mechanical Reference Design Figure 2-6. TCONTROL and Fan Speed Control Once the TCONTROL value is determined as explained earlier, the thermal diode temperature reading from the processor can be compared to this TCONTROL value. A fan speed control scheme can be implemented as described in Table 2-3 without compromising the long-term reliability of the processor. Table 2-3.
Thermal/Mechanical Reference Design convenient in that it is calculated using total package power, whereas actual thermal resistance, θ (theta), is calculated using actual power dissipated between two points. Measuring actual power dissipated into the heatsink is difficult, since some of the power is dissipated via heat transfer into the socket and board. Be aware, however, of the limitations of lumped parameters such as Ψ when it comes to a real design.
Thermal/Mechanical Reference Design Figure 2-7. Processor Thermal Characterization Parameter Relationships 2.3.2.1 Example The cooling performance, ΨCA, is then defined using the principle of thermal characterization parameter described above: • Define a target case temperature TCASE-MAX and corresponding TDP at a target frequency, F, given in the processor datasheet. • Define a target local ambient temperature at the processor, TLA.
Thermal/Mechanical Reference Design Equation 2-7. ΨCA = (TCASE – TLA) / TDP = (68 – 40) / 85 = 0.33 °C/W It is evident from the above calculations that, a reduction in the local processor ambient temperature has a significant positive effect on the case-to-ambient thermal resistance requirement. 2.3.3 Chassis Thermal Design Considerations 2.3.3.
Thermal/Mechanical Reference Design effective heat transfer surface area by conducting heat out of the IHS and into the surrounding air through fins attached to the heatsink base. • The conduction path from the heat source to the heatsink fins - Providing a direct conduction path from the heat source to the heatsink fins and selecting materials with higher thermal conductivity typically improves heatsink performance.
Thermal/Mechanical Reference Design 2.4.3 Summary In summary, considerations in heatsink design include: • The local ambient temperature TLA at the heatsink, airflow (CFM), the power being dissipated by the processor, and the corresponding maximum TCASE. These parameters are usually combined in a single lump cooling performance parameter, ΨCA (case to air thermal characterization parameter). More information on the definition and the use of ΨCA is given in Section 2.4 and Section 2.3.2. • • • • • • 2.
Thermal/Mechanical Reference Design 2.4.4.2 Assembly Drawing Figure 2-8. Exploded View of CEK Thermal Solution Components The CEK reference thermal solution is designed to extend air-cooling capability through the use of larger heatsinks with minimal airflow blockage and bypass. CEK retention solution can allow the use of much heavier heatsink masses compared to the legacy limits by using a load path directly attached to the chassis pan.
Thermal/Mechanical Reference Design design and the standoff heights, may need to change. Therefore, system designers need to evaluate the thermal performance and mechanical behavior of the CEK design on baseboards with different thicknesses. Refer to Appendix A for drawings of the heatsinks and CEK spring. The screws and standoffs are standard components that are made captive to the heatsink for ease of handling and assembly.
Thermal/Mechanical Reference Design Figure 2-9. 2U+ CEK Heatsink Thermal Performance If other custom heatsinks are intended for use with the 64-bit Intel Xeon Processor with 2MB L2 Cache, they must support the following interface control requirements to be compatible with the reference mechanical components: • Requirement 1: Heatsink assembly must stay within the volumetric keep-in. • Requirement 2: Maximum mass and center of gravity. Current maximum heatsink mass is 1000 grams [2.
Thermal/Mechanical Reference Design Figure 2-10. 1U CEK Heatsink Thermal Performance 2.4.6 Thermal Profile Adherence The 2U+ CEK Intel reference thermal solution is designed to meet the Thermal Profile A for the 64-bit Intel Xeon Processor with 2MB L2 Cache. From Table 2-2, the three-sigma (mean+3sigma) performance of the thermal solution is computed to be 0.293 °C/W and the processor local ambient temperature (TLA) for this thermal solution is 40 °C.
Thermal/Mechanical Reference Design Figure 2-11. 2U+ CEK Thermal Adherence to 64-bit Intel® Xeon™ Processor with 2MB L2 Cache Thermal Profile A The 1U CEK Intel reference thermal solution is designed to meet the Thermal Profile B for the 64bit Intel Xeon Processor with 2MB L2 Cache. From Table 2-2, the three-sigma (mean+3sigma) performance of the thermal solution is computed to be 0.346 °C/W and the processor local ambient temperature (TLA) for this thermal solution is 40 °C.
Thermal/Mechanical Reference Design Figure 2-12. 1U CEK Thermal Adherence to 64-bit Intel® Xeon™ Processor with 2MB L2 Cache Thermal Profile B 2.4.7 Components Overview 2.4.7.1 Heatsink with Captive Screws and Standoffs The CEK reference heatsink uses snapped-fin technology for its design. It consists of a copper base and copper fins with Shin-Etsu* G751 thermal grease as the TIM.
Thermal/Mechanical Reference Design Figure 2-13. Isometric View of the 2U+ CEK Heatsink Note: Refer to Appendix A for more detailed mechanical drawings of the heatsink. Figure 2-14. Isometric View of the 1U CEK Heatsink Note: Refer to Appendix A for more detailed mechanical drawings of the heatsink. The function of the standoffs is to provide a bridge between the chassis and the heatsink for attaching and load carrying.
Thermal/Mechanical Reference Design The function of the screw is to provide a rigid attach method to sandwich the entire CEK assembly together, activating the CEK spring under the baseboard, and thus providing the TIM preload. A screw is an inexpensive, low profile solution that does not negatively impact the thermal performance of the heatsink due to air blockage. Any fastener (i.e.
Thermal/Mechanical Reference Design when the baseboard is pushed down upon it. This spring does not function as a clip of any kind. The two tabs on the spring are used to provide the necessary compressive preload for the TIM when the whole solution is assembled. The tabs make contact on the secondary side of the baseboard. In order to avoid damage to the contact locations on the baseboard, the tabs will be insulated with a 0.127 mm [0.005 in.] thick Kapton* tape (or equivalent).
Thermal/Mechanical Reference Design products is called the Common Enabling Kit, or CEK. The CEK base is compatible with all three heatsink solutions. Figure 2-17 provides a representation of the active CEK solution. This design is based on a 4-pin PWM/T-diode controlled active fan heatsink solution. This new solution is being offered to help provide better control over pedestal chassis acoustics.
Thermal/Mechanical Reference Design The fan outputs a SENSE signal, an open-collector output, which pulses at a rate of two pulses per fan revolution. A baseboard pull-up resistor provides VCC to match the baseboard-mounted fan speed monitor requirements, if applicable. Use of the SENSE signal is optional. If the SENSE signal is not used, pin 3 of the connector should be tied to GND.
Thermal/Mechanical Reference Design 2.4.8.2 Systems Considerations Associated with the Active CEK This heatsink was designed to help pedestal chassis users to meet the thermal processor requirements without the use of chassis ducting. It may be necessary to implement some form of chassis air guide or air duct to meet the TLA temperature of 40 °C depending on the pedestal chassis layout.
Thermal/Mechanical Reference Design 38 64-bit Intel® Xeon™ Processor with 2MB L2 Cache Thermal/Mechanical Design Guidelines
A Mechanical Drawings The mechanical drawings included in this appendix refer to the thermal mechanical enabling components for the 64-bit Intel® Xeon™ Processor with 1MB L2 Cache. Note: Intel reserves the right to make changes and modifications to the design as necessary. Table A-1.
Mechanical Drawings Figure A-1.
Mechanical Drawings Figure A-2.
Mechanical Drawings Figure A-3.
Mechanical Drawings Figure A-4.
Mechanical Drawings Figure A-5.
Mechanical Drawings Figure A-6.
Mechanical Drawings Figure A-7.
Mechanical Drawings Figure A-8.
Mechanical Drawings Figure A-9.
Mechanical Drawings Figure A-10.
Mechanical Drawings Figure A-11.
Mechanical Drawings Figure A-12.
Mechanical Drawings Figure A-13.
Mechanical Drawings Figure A-14.
Mechanical Drawings Figure A-15.
Mechanical Drawings Figure A-16.
Mechanical Drawings Figure A-17.
Mechanical Drawings Figure A-18.
Mechanical Drawings Figure A-19.
Mechanical Drawings Figure A-20.
Mechanical Drawings 60 64-bit Intel® Xeon™ Processor with 2MB L2 Cache Thermal/Mechanical Design Guidelines
B Safety Requirements Heatsink and attachment assemblies shall be consistent with the manufacture of units that meet the safety standards: 1. UL Recognition-approved for flammability at the system level. All mechanical and thermal enabling components must be a minimum UL94V-2 approved. 2. CSA Certification. All mechanical and thermal enabling components must have CSA certification. 3. Heatsink fins must meet the test requirements of UL1439 for sharp edges.
Safety Requirements 62 64-bit Intel® Xeon™ Processor with 2MB L2 Cache Thermal/Mechanical Design Guidelines
C Quality and Reliability Requirements C.1 Intel Verification Criteria for the Reference Designs C.1.1 Reference Heatsink Thermal Verification The Intel reference heatsinks will be verified within specific boundary conditions using a TTV and the methodology described in the Intel® Xeon™ Processor Family Thermal Test Vehicle User's Guide.
Quality and Reliability Requirements Figure C-1. Random Vibration PSD C.1.2.3 Shock Test Procedure Recommended performance requirement for a baseboard: • Quantity: 3 drops for + and – directions in each of 3 perpendicular axes (i.e. total 18 drops). • Profile: 50 G trapezoidal waveform, 11 ms duration, 4.32 m/sec minimum velocity change. • Setup: Mount sample board on test fixture. Figure C-2.
Quality and Reliability Requirements C.1.2.4 Recommended Test Sequence Each test sequence should start with components (i.e. baseboard, heatsink assembly, etc.) that have not been previously submitted to any reliability testing. The test sequence should always start with a visual inspection after assembly, and BIOS/Processor/ memory test. The stress test should be then followed by a visual inspection and then BIOS/ Processor/memory test. C.1.2.
Quality and Reliability Requirements Material used shall not have deformation or degradation in a temperature life test. Any plastic component exceeding 25 grams must be recyclable per the European Blue Angel recycling standards.
D Enabled Suppliers Information D.1 Supplier Information D.1.1 Intel Enabled Suppliers The Intel reference solutions have been verified to meet the criteria outlined in Section D.1. Customers can purchase the Intel reference thermal solution components from the suppliers listed in Table D-1.
Enabled Suppliers Information D.1.2 Additional Suppliers As mentioned in Appendix E.1.1, the Intel 64-bit Intel Xeon Processor with 2MB L2 Cache Reference Design (CEK604-1U-02) was optimized for thermal performance to meet Thermal Profile B in 1U rack optimized servers. Similar optimizations can be achieved with heatsinks designs from multiple suppliers of Intel Xeon processor with 800 MHz System Bus heatsinks.
E Processor Thermal Management Logic and Thermal Monitor Features E.1 Thermal Management Logic and Thermal Monitor Feature E.1.1 Processor Power Dissipation An increase in processor operating frequency not only increases system performance, but also increases the processor power dissipation. The relationship between frequency and power is generalized in the following equation: P = CV2F (where P = power, C = capacitance, V = voltage, F = frequency).
Processor Thermal Management Logic and Thermal Monitor Features temperature. By comparing this current with the reference current, the processor temperature can be determined. The reference current source corresponds to the diode current when at the maximum permissible processor operating temperature. Processors are calibrated during manufacturing on a small sample set. Once configured, the processor temperature at which the PROCHOT# signal is asserted (trip point) is not re-configurable. Figure E-1.
Processor Thermal Management Logic and Thermal Monitor Features Figure E-2. Concept for Clocks under Thermal Monitor Control E.1.3 Operation and Configuration To maintain compatibility with previous generations of processors, which have no integrated thermal logic, the TCC portion of Thermal Monitor is disabled by default. During the boot process, the BIOS must enable the TCC; or a software driver may do this after the operating system has booted.
Processor Thermal Management Logic and Thermal Monitor Features Cache Versions) Specification Update when available. For more details also refer to IA-32 Intel® Architecture Software Developer's Manual Volume 3: System Programming Guide. When Thermal Monitor 2 is enabled, and a high temperature situation is detected, the enhanced TCC will be activated. The enhanced TCC causes the processor to adjust its operating frequency (bus-to-core multiplier) and input voltage identification (VID) value.
Processor Thermal Management Logic and Thermal Monitor Features E.1.5 System Considerations The Thermal Monitor feature may be used in a variety of ways, depending upon the system design requirements and capabilities. • Intel requires the TCC to be enabled for all 64-bit Intel Xeon Processor with 2MB L2 Cache-based systems. At a minimum, the TCC provides an added level of protection against processor thermal solution failure.
Processor Thermal Management Logic and Thermal Monitor Features the on-die thermal diode and the Thermal Monitor’s temperature sensor. This temperature variability across the die is highly dependent on the application being run. As a result, it is not possible to predict the activation of the TCC by monitoring the on-die thermal diode.
Processor Thermal Management Logic and Thermal Monitor Features Figure E-4. On-Die Thermal Diode Sensor Time Delay E.1.8.1 THERMTRIP# Signal Pin In the event of a catastrophic cooling failure, the processor will automatically shut down when the silicon temperature has reached its operating limit. At this point the system bus signal THERMTRIP# signal goes active and power must be removed from the processor. THERMTRIP# stays active until RESET# has been initiated.
Processor Thermal Management Logic and Thermal Monitor Features E.1.9 Cooling System Failure Warning §If desired, the system may be designed to cool the maximum processor power. In this situation, it may be useful to use the PROCHOT# signal as an indication of cooling system failure. Messages could be sent to the system administrator to warn of the cooling failure, while the TCC would allow the system to continue functioning or allow a graceful system shutdown.
