Q: I'm having a problem with performance in my ASP.NET master page. In the debugger I see the master page runs during each postback. How do we stop the master page from running its Load event each time?
A: The MasterPage class derives from UserControl, which gives a hint as to why the master behaves this way. The master page becomes a control inside the page, and like every control in ASP.NET the master recreates itself on every postback (see Master Pages: Tips, Tricks, and Traps).
You might be able to improve the situation using some common ASP.NET performance tips: