In doing some DFS-R troubleshooting I came across the directory services team blog.  The DS team blog might seem like the place to go for Active Directory insights but they do have a good bit of information around DFS as well.

You can read the full article here, but I’ve listed the top ten causes of slow replication below:

1. Missing Windows Server 2003 Network QFE Hotfixes or Service Pack 2
2. Missing DFSR Service’s latest binary
3. Out-of-date Network Card and Storage drivers
4. DFSR Staging directory is too small for the amount of data being modified
5. Bandwidth Throttling or Schedule windows are too aggressive
6. Large amounts of sharing violations
7. RDC has been disabled over a WAN link
8. Incompatible Anti-Virus software or other file system filter drivers
9. File Server Resource Manager (FSRM) configured with quotas/screens that block replication
10. Un-staged or improperly pre-staged data leading to slow initial replication