Here is a very intriguing snippet of the article:
The other notable performance feature in IIS 7.0 is the new IIS Output Cache. This feature provides support for re-using responses to expensive dynamic pages on the server, alleviating the need to perform the expensive rendering and database transactions in order to return the response to the client. The IIS Output Cache is a faster alternative to the existing rich output caching feature in ASP.NET, supporting a smaller set of caching functionality but providing enough flexibility to cache dynamic content in a performance-enhancing way.
By output caching your dynamic content, whether it is ASP.NET pages, PHP scripts, or CGI applications, you can frequently get a 5-10 times performance boost with much less load on your disk and database.