Entity framework uses a lot of memory

I have a hunch you don't dispose the context.
I suggest disposing the context whenever you done interacting with database.

Use using statement whenever you create the context.

[Edit]

As far as I can see, you cache and don't dispose your EFUnitOfWork object. It is disposable, which is correct, but I don't see when disposable is called. Seems like you hold a reference to the context for all application run time.
Moreover, you create and hold one context per thread, which will make it even worse.

I can't tell you for sure where you should put Dispose or using, as I don't know the usages.
You could put it probably to your Commit method, but I don't know if the Commit called only once during database interaction session.

Also, your design might be overcomplicated.

If I were you, I would:

• Find the way to dispose the context using current code, as a short-term solution
• Simplify the design, as the long-term solution

If I had time I would do long-term solution right away.
But again, I can't tell if the complexity of your design is justified, as I don't know how big your application is and what it does and what the requirements are.

Couple of things come to my mind:

• You aren't probably Disposing the ObjectContext. Make sure all your database codes are within using(var context = CreateObjectContext()) block
• You have an N-tier architecture and you are passing entities from the data access layer to upper layer without Detaching the entities from ObjectContext. You need to call ObjectContext.Detach(...)
• You are most likely returning a full collection of entities, instead of returning a single enity for single Get operations. For ex, you have queries like from customer in context.Customers select customer instead of doing from customer in context.Customers select customer.FirstOrDefault()

I have had hard time making Entity Framework to work in an N-tier application. It's just not suitable for using in N-tier apps as is. Only EF 4.0 is. You can read about all my adventure in making EF 3 work in an N-tier app.

http://www.codeproject.com/KB/linq/ef.aspx

Does this answer your question?