Static assemblies are stored on disk.But dynamic assemblies 
are directley loaded from memory.

Assemblies can be static or dynamic. Static assemblies can 
include .NET Framework types (interfaces and classes), as 
well as resources for the assembly (bitmaps, JPEG files, 
resource files, and so on). Static assemblies are stored on 
disk in PE files. You can also use the .NET Framework to 
create dynamic assemblies, which are run directly from 
memory and are not saved to disk before execution. You can 
save dynamic assemblies to disk after they have executed.