PerformancePoint Server Planning/Architecture, Deployment and Operations Guides and White Papers: these can all be found on Microsoft TechNet

http://technet.microsoft.com/en-us/library/bb794633.aspx

White paper: Performance tuning and capacity planning for PerformancePoint Monitoring Server

This white paper is for Microsoft Office PerformancePoint Server 2007 administrators and IT professionals who want guidance about Monitoring Server performance capabilities. This guidance includes how performance is affected by security settings, number of users, scalability, and load capacity, among other areas. Considerations for hardware planning, dashboard composition, physical memory, and virtual machines are also covered.

White paper: Performance tuning for PerformancePoint Planning Server

This white paper is for analysts and IT professionals who want guidance about PerformancePoint Planning Server scalability capabilities and the number of users that can be served. Considerations for hardware planning and software tuning are also covered.