Intel Xeon Processor Multiprocessor Platform Design Guide

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System Bus Routing
6.4.1.6 Design Considerations
Intel has found that the following recommendations provide one method of designing a 4-way
processor platform. This is a baseline configuration only. Modify this baseline as needed while
adhering to the above Design Recommendations.
• Maintain a trace width of 4.0 mil to provide a 47 Ω trace impedance.
• Trace to trace spacing of 16-mil edge-to-edge (except in component breakout where spacing is
constrained)
• Rotate the processor socket such that the data pins are closest to the chipset making data the
shortest signals.
Figure 6-7. Wired-OR Topology
Chipset
Proc 4
Proc 3
Proc 2Proc 1
143 Ω
Vcc_CPU
143 Ω
Vcc_CPU
143 Ω
Vcc_CPU
L4 L3
L2
L1