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System Memory Design Guidelines (DDR-SDRAM)
R
152
Intel
®
855PM Chipset Platform Design Guide
Figure 86. SCK/SCK# Trace Length Matching Requirements
SO-DIMM0
= Motherboard Trace Lengths
Note: Lengths are measured from MCH-M pin to SO-
DIMM0 connector pads.
SCK0
SCK#0
SCK1
SCK#1
SCK2
SCK#2
SCK0 Length = X
0
SCK#0 Length = X
0#
SCK1 Length = X
1
SCK#1 Length = X
1#
SCK2 Length = X
2
SCK#2 Length = X
2#
SO-DIMM0 SO-DIMM1
= Motherboard Trace Lengths
Intel 855PM
MCH Package
Note: Lengths are measured from MCH-M pin to SO-
DIMM1 connector pads.
Intel 855PM
MCH Package
|X
0
- X
0#
| <= 0.01 inches
SCK3
SCK#3
SCK4
SCK#4
SCK5
SCK#5
SCK3 Length = Y
0
SCK#3 Length = Y
0#
SCK4 Length = Y
1
SCK#4 Length = Y
1#
SCK5 Length = Y
2
SCK#5 Length = Y
2#
|X
1
- X
1#
| <= 0.01 inches
|X
2
- X
2#
| <= 0.01 inches
|Y
0
- Y
0#
| <= 0.01 inches
|Y
1
- Y
1#
| <= 0.01 inches
|Y
2
- Y
2#
| <= 0.01 inches