http://dotnetperls.com/precompiled-aspnet
Target Location:
[Text input box]
This is where the published site will be put.
(The author suggests using a location on your disk C:/ for now.)
"Allow this precompiled site to be updatable"
[X]
This indicates whether you want to use dynamic compilation or not. Your
website is only updatable if you do not compile it all into a big assembly before
you deploy it.
"Use fixed naming and single-page assemblies"
[X]
Fixed naming is naming that is always the same.
The author recommends this as it will allow to easily replace old assemblies on
the server.
"Enable strong naming on precompiled assemblies"
[X]
This is a security option.
Points on options. There are a couple points about these options the author wants to stress. The first checkbox above, "Allow this... to be updatable" is actually Microsoft's way of saying "Use dynamic compilation". With this option, all of your pages will be compiled at the last moment. This can be very slow.
note: from envykok
"Allow this... to be updatable"-only when u used this page, it will be compiled
How can I use the fastest compilation mode?
If by fastest you mean for the site once deployed, then we must use "site precompilation." Let's assume your site is high-volume, popular, and important to you. It is important that the site respond instantly when a potential customer comes along. Definitely use site compilation. Here are the steps to enable site compilation.
Check target location. The target publish location is probably already set, but if it isn't, set the target location to your C:/ drive.
Uncheck "updatable" box. Allowing your site to be updatable will make it slower. Therefore, for site precompilation uncheck this box.
Check "use fixed naming". Fixed naming makes it easier to drag and drop your new DLL to the old DLL location and replace the files. That's all this option is good for, but this is really handy and it is best to use fixed naming.
Verify that it worked. Open your Projects folder in the Documents > Visual Studio 2008 folder. Your precompiled site will be in the folder corresponding to your site's name. It should be in the PrecompiledWeb folder.
Note on Web Application projects. The Web Application project type is another model for creating ASP.NET sites. It does not have the same precompiled options, but you can use Publish for the same effect.