Does a .NET 4.0 website load faster for a reason?

Question

I have been using DotNetBlogEngine for many years, and today my host (JodoHost.com) officially turned on support for .NET 4.0. I had them change my site from a 2.0 application to a 4.0 application and planned on recompiling the site if I had to. What I've noticed immediately is that the website loads tremendously faster on the first load, subsequent loads are only slightly faster.

The website is compiled as a .NET 2.0 web application, there was no need for a recompile of the site.

Is there a known reason for this performance increase? Was there a change in the .NET 4.0 framework that improved the initial load time of websites into an application pool?

This is hosted on a 2003 server.

Here is the site for reference: http://www.ocdprogrammer.com

Answer 1

Probably doesn't explain a huge speedup, but please see: .NET 4 Web Application Startup Time:

... there's a switch in C:\Windows\Microsoft.NET\Framework\v4.0.xxxx\Aspnet.config called shadowCopyVerifyByTimestamp that ASP.NET uses to startup up the CLR. The CLR optimized in .NET 4 how shadow copy assemblies are loaded by removing an unnecessary file copy if nothing's changed. Hence, part of the improvement in cold web app startup.