You might need to change the default FRS replication schedules for SYSVOL and DFS replicas to maximize your network bandwidth. Keep in mind as you consider your replication schedule that FRS replicates whole files, and this can impact the network bandwidth that is available. You might decide, for example, to schedule replication during off hours in order to maximize your bandwidth during business hours. Becoming familiar with the procedures for configuring replication schedules for both DFS and SYSVOL will assist you in scheduling replication for your organization.
You can build a staggered and well-balanced topology using the MKDSX scripts from the Branch Office Deployment Guide available at http://go.microsoft.com/fwlink/?LinkId=16718.
Detailed discussion of this subject is beyond the scope of this document. However, for Active Directory replication, a rule of thumb is that a given domain controller that acts as a bridgehead server should not have more than 50 active simultaneous replication connections at any given time in a replication window. This was determined on a reference server that had four Pentium III Xeon processors with 2 gigabytes (GB) of RAM and 2 megabytes (MB) of L2 cache. Adjusting this rule to a limit of fewer than 50 servers will have significant positive impact on CPU utilization, network throughput, and I/O throughput on this domain controller
For additional information about scheduling replication, see Scheduling SYSVOL Replication and Scheduling FRS Replication for DFS Replica Sets.