You can break up a single SWF into multiple SWFs using the Flex concept of
Modules. And because you have smart code running, you have the option of
pre-fetching some of those modules while the user is interacting with the
Thanks for your reply
can you please provide me any link where all this is explained in detail.Any demo application of that type will be of great help.Thanks once again.
See the documentation for mx:ModuleLoader and mx:Module.
This seems more of an RIA performance question than a Flex specific one. Honestly though, modules aren't needed often in my experience (depends greatly on requirements).
You say that "only the part of the application that is needed" is downloaded, while this is technically true (a bit of an oversimplification as there are other advantages to be had from RIAs), you still have the round trip time required for every single request to the server. Since an RIA is generally a single bulk download (which may not even be needed if there's caching going on), usually you're talking about a single wait of a few seconds for loading vs multiple waits of a few seconds for page refreshes.
Even if the initial load time is as much as ~10 seconds (for the first visit), does that outweigh the 1 to 3+ second page refresh penalty constantly interrupting the user's work flow over time? Also consider Flex's AMF protocol, which blows competing formats (esp XML based) out of the water on performance. RIAs (especially Flex) win the performance game.