As I can see, beta2 of .Net Framework 4.0 installation program is only 55MB, and it was 200+MB for .Net 3.5, What's happening?
.NET 3.5 size is that big because it contains the x64 version of the framework in the same package. The 2.0, 3.0 packages were separated for x86 vs x64. I guess 4.0 will adopt a separated approach too. This link explains it: link