Intel QX9770 Design Guidelines - Page 40

LGA775 Socket Heatsink Loading

40

Thermal and Mechanical Design Guidelines

5.1.1

Heatsink Performance

Table 2 provides the Intel ALCT Reference Design performance for the Intel

®

Core™2

Extreme processor QX6800 B3 Stepping and QX9770 C0 Stepping.

The results are

based on the test procedure described in Section

5.1.4.

The table also includes a T

A

assumption of 38 °C for the Intel reference thermal

solution at the inlet to the heat exchanger fan discussed in Section

3.3. An external

ambient temperature to the chassis of 35 °C is assumed, resulting in a temperature

rise, T

R

, of 3 °C. Meeting T

A

and

Ψ

CA

targets can maximize processor performance

(refer to Sections

2.2,

2.4. and Chapter

4). Minimizing T

R

, can lead to improved

acoustics.

Table 2. Intel Liquid Cooled Reference Design Performance (ALCT)

Processor

Target Thermal

Performance,

Ψ

ca

(Mean + 3

σ

)

T

A

Assumption

Intel

®

Core™ 2 Extreme processor QX6800 B3 stepping

0.13

°

C/W

T

A

= 38

°

C

Intel

®

Core™ 2 Extreme processor QX9770 C0 stepping

0.13

°

C/W

T

A

= 38

°

C

5.1.2

Acoustics

To optimize acoustic emission by the heat exchanger fan and pump, the reference

design implements a variable speed fan and pump.

A variable speed fan and pump

allows the reference design performance to adjust for changes in processor utilization

and ambient air conditions. The required fan speed necessary to meet thermal

specifications can be controlled by the silicon sensor temperature and should comply

with requirements in Table 3.

Table 3. Acoustic Results

Fan Speed

PWM

(RPM)

Pump Speed

PWM

(RPM)

Acoustic

Thermal

Performance

Ψ

ca

Descriptions

100%

(3300)

100%

(1700)

6.0BA

0.13

°

C/W

Maximum fan and pump

speed

25%

(900)

25%

(600)

3.6BA

~0.23

°

C/W

Minimum fan and pump

speed

NOTES:

1.

Acoustic performance is defined in terms of measured sound power (LwAm) as defined in

ISO 9296 standard, and measured according to ISO 7779.

2.

Pump speed represents 3 pulses per rotation and if read by MB circuitry that assumes 2

pulses per rotation. It will perceive its operating (rotating) faster than specified in the table

(e.g., the real pump speed is 600 rpm, 3 pulses, but MB would report 900rpm per 2 pulses

calculated.)

3.

If only 3 pin headers are available on MB that operate at a constant 12 V, the fan and

pump will operate at full speed and this condition does not represent the minimum speed.

The design is intended to run using 4 pin header PWM signals specified in Sections

5.1.5

and

5.1.6.

4.

If only one

4 pin header is available on MB (all others are 3 pin headers), it is

recommended to run the pump off of the 4 pin header and the fan off of the 3 pin header

and to have both headers respond to the CPU temperature to deliver the performance

indicated in Table 3.

Section	Page
1 Introduction	9
1.1 Document Goals and Scope	9
1.1.1 Importance of Thermal Management	9
1.1.2 Document Goals	9
1.1.3 Document Scope	10
1.2 References	11
1.3 Definition of Terms	11
2 Processor Thermal/Mechanical Information	13
2.1 Mechanical Requirements	13
2.1.1 Processor Package	13
2.1.2 Heatsink Attach	15
2.1.2.1 General Guidelines	15
2.1.2.2 The Pump Assembly Clip Load Requirement	15
2.1.2.3 Additional Guidelines	16
2.2 Thermal Requirements	16
2.2.1 Processor Case Temperature	16
2.2.2 Thermal Profile	17
2.2.3 TCONTROL	18
2.3 Heatsink Design Considerations	19
2.3.1 Heatsink Size	20
2.3.2 Package IHS Flatness	20
2.3.3 Thermal Interface Material	21
2.4 System Thermal Solution Considerations	21
2.4.1 Chassis Thermal Design Capabilities	21
2.4.2 Improving Chassis Thermal Performance	21
2.4.3 Summary	22
2.5 System Integration Considerations	22
3 Thermal Metrology	23
3.1 Characterizing Cooling Performance Requirements	23
3.1.1 Example	25
3.2 Processor Thermal Solution Performance Assessment	26
3.3 Local Ambient Temperature Measurement Guidelines	26
3.4 Processor Case Temperature Measurement Guidelines	29
4 Thermal Management Logic and Thermal Monitor Feature	31
4.1 Processor Power Dissipation	31
4.2 Thermal Monitor Implementation	31
4.2.1 PROCHOT# Signal	32
4.2.2 Thermal Control Circuit	32
4.2.3 Thermal Monitor 2	33
4.2.4 Operation and Configuration	34
4.2.5 On-Demand Mode	35
4.2.6 System Considerations	35
4.2.7 Operating System and Application Software Considerations	36
4.2.8 THERMTRIP# Signal	36
4.2.9 Cooling System Failure Warning	36
4.2.10 Digital Thermal Sensor	37
4.2.11 Platform Environmental Control Interface (PECI)	38
5 Intel Thermal/Mechanical Reference Design Information	39
5.1 Validation Results for the ATX Reference Design	39
5.1.1 Heatsink Performance	40
5.1.2 Acoustics	40
5.1.3 Altitude	41
5.1.4 Reference Heatsink Thermal Validation	41
5.1.5 Fan Motor Performance	42
5.1.6 Pump Motor Performance	43
5.2 Environmental Reliability Testing	44
5.2.1 Structural Reliability Testing	44
5.2.1.1 Random Vibration Test Procedure	44
5.2.1.2 Shock Test Procedure	45
5.2.2 Power Cycling	46
5.2.3 Reliability Testing	46
5.2.3.1 Tubing Material Selection	48
5.2.3.2 Reservoir Sizing	48
5.2.3.3 Reliability Test Results	50
5.2.4 Recommended BIOS/CPU/Memory Test Procedures	51
5.3 Material and Recycling Requirements	52
5.4 Safety Requirements	52
5.5 Geometric Envelope for Intel Reference ATX Thermal Mechanical Design	52
5.6 Reference Attach Mechanism	54
5.7 Socket and Voltage Regulation Cooling Strategy	55
6 Intel® Quiet System Technology (Intel® QST)	57
6.1 Intel® Quiet System Technology Algorithm	57
6.1.1 Output Weighting Matrix	58
6.1.2 Proportional-Integral-Derivative (PID)	58
6.2 Board and System Implementation of Intel® Quiet System Technology	60
6.3 Intel® QST Configuration & Tuning	62

Intel QX9770 Design Guidelines - Page 40

Heatsink Performance, 5.1.2 Acoustics - cpu

Page 40 highlights