Pav Cherny has published another interesting article – “Inside SharePoint: Improving SharePoint Performance” in the August 2009 issue of TechNet Magazine. In it Pav presents an overview of key SharePoint architecture components, describes how they can lead to common performance issues, and discusses how to resolve and troubleshoot problems.
Though there is lot of material available on TechNet website on SharePoint performance, this article does a very good summarization of issues, causes and possible resolutions and provides links to relevant resources for further reading.
For those interesting in knowing how Microsoft IT does it internally in Microsoft, I would recommend the White Paper - “SharePoint Performance Optimization: How Microsoft IT Increases Availability and Decreases Rendering Time of SharePoint Sites” available in SharePoint Server area of Microsoft IT Showcase.
Given below are some other articles by Pav which I would recommend reading: