assembly-csharp.dll took too much time to load.(wp8) please help

Hi there,

I 'm using 4.3.1f.
I want to optimize game launch time on windows phone 8.
Launch time below means time between click app icon and render first screen (not splash screen)

I found most of the time is used to load assembly-csharp.cs.
I am using lower-end 512RAM device to test. I can get half of launch time on higher-end device.

project have only scripts, any other type of assets do not exist.
Launch a empty windows phone 8 unity project (one scene, one camera, nothing more) takes 2.7s.

Launch a empty windows phone 8 unity project with 2dtoolkit (not using 2dtoolkit at all) takes 5s.
assembly-csharp.dll 293kb

Launch a empty windows phone 8 unity project with 2dtoolkit plus my own game’s scripts (60 c# scripts) takes 9s.
assembly-csharp.dll 603kb

BTW, I thought unity only compile necessary scripts into assembly-csharp.dll ,but actually it compiles all the scripts in the project except editor only.

Could any one help me where is the problem and what I should do.
I will update result on 4.5.3 later.

Yes, it is the stupid 4.3.1 problem.
Uniy3.5.3 works much better for me now and it render whole game’s first screen within 5s