Send large byte arrays between AppDomains in the same process

TCP binary remoting is certainly fast, I do not how much faster it is than raw sockets which is probably the fastest, but a royal PIA.

I have run 1500 - 2000 req per second in production using HTTP binary remoting between two boxes. On the same box you should have much high performance using TCP or a name pipes channel, depending in the CPU cycles it takes to process the data.

If I was you I would take a look at how Cassini is implemented. It does pretty much exactly what you are talking about doing.

Actually Cassini has been sort of superceded by Webhost which is the built-in webserver that ships with Visual Studio now. Take a look at this post on Phil Haack's blog for more.

Very good question. If I were coming at this problem I would probably use a Buffered Stream / Memory Stream and marshal the stream into the AppDomain that consumes the object to reduce marshaling or serializing many object graphs that were created in a different AppDomain.

But then again, it sounds like you are almost completely duplicating the functionality of IIS, so I would look/reflector into the System.Web.Hosting namespace and see how they handle it and their WorkerThreadPool etc....