Intel 41210 Design Manual page 47

Table 15. Adapter Card Routing Recommendations (Sheet 2 of 2)
Receive Trace Length (Card
edge finger to 41210 Bridge
receiver pin
Length Matching
Requirements:
Number of vias
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
1.0" min - 6.0" max
Total allowable intra-pair length mis-match must not exceed 25 mils. Each
routing segment should be matched as close as possible. Total skew across all
lanes must be less than 20 ns. See the PCI-Express Desktop Design Guidelines
for additional routing requirements
4 max
PCI Express Layout
47