The caching of the Dashboard Definitions Catalog is a first step in optimizing your portal's performance that was introduced with Service Pack 1. All Web Parts of a dashboard with this caching enabled will still be executed, while this often may not be necessary. Instead, the HTML output generated from the assembly of all Web Parts of a dashboard can be cached for all users. This is known as full-page caching, a new feature added in Service Pack 1.
Full-page caching will look at the caching options for each Web Part of the dashboard. If “All User” caching is not enabled for all Web Parts (except for the Search Web Part), full-page caching does not work.
Under the Hood: The Search Web Part
Let's examine that “except for the ...