Mechanical Enabling for the Intel Pentium 4 Processor in the 478-Pin Package

Design Effectiveness

Solder Joint Considerations - 4

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Compressive Preload

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Places MB into concave curvature in local region surrounding socket

and MCH

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Outer row solder balls placed in compression

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Delays onset of critical tensile load during shock

RM /ClipRM /Clip

Pre-stresses critical

solder balls with

compression

Note: Applying a compressive preload on the processor package and on the MCH creates a bow to the board as

described reference [6], slide 25. The Intel reference mechanical system designed for the Intel® Pentium® 4

processor in the 478-pin package has passed shock, vibration and long term reliability tests defined by Intel. Intel

reference designs were tested in conjunction with the reference Intel® 845 MCH heatsink assembly. No platform

failures related to board flexure were identified in long term reliability testing. This conclusion assumes that there

is no change to the elements of the reference design assembly, and that it is used in conjunction with the

reference Intel

845 MCH assembly. Customers are responsible to fully validate the design they intend to use.