Microsoft's Steffen Krause has written an excellent whitepaper on Tuning the Performance of Change Data Capture in SQL Server 2008, that I technically reviewed, and it was published late last year. To get an overview of Change Data Capture (CDC) before reading the whitepaper, see the TechNet Magazine article I wrote for the November issue, titled SQL Server 2008: Tracking Changes in Your Enterprise Database. The new whitepaper covers:

• Configuration of sys.sp_cdc_enable_table parameters
• Configuration of the CDC capture job
• Using Extended Events to determine the performance and characteristics of CDC
• Influence of CDC scan job parameters on CDC performance
• Influence of workload characteristics on CDC performance
• Influence of sys.sp_cdc_enable_table parameters on CDC performance
• CDC cleanup job considerations
• Transaction log file considerations

Check it out at http://msdn.microsoft.com/en-us/library/dd266396.aspx.