The data-access adapter class is very fast when instantiating but when you instantiate it for the first time, it will trigger e.g. the static constructor of the persistenceinfo class and other classes which build meta-data structures in memory. This is a one-time thing, but if your model is really large (e.g. 1000 entities or more) it can take some time (1-2seconds). That's why I asked you to profile the methods called as children of the constructor call (profilers usually show these methods as 'children' of the constructor call, also static constructors of other classes). For instance the query engine's static constructors are called at that moment as well, reading config data from the app/web.config file.
If this is a small model, then it's odd it takes that long, hence you should check what code is triggered by the constructor (i.e. which static constructors are slow). the constructor itself doesn't do much.