according to this article, WCF with named pipes is the best choice for IPC, and it is around 25 % faster than .Net Remoting.
I have the following code that compares WCF
Wcf: 261,03 ms.
Wcf: 247,02 ms.
Wcf: 236,02 ms.
Wcf: 235,02 ms.
Wcf: 236,02 ms.
WCF NetNamedPipeBinding done. Avg : 243,02
Wcf: 508,05 ms.
Wcf: 467,05 ms.
Wcf: 484,05 ms.
Wcf: 458,05 ms.
Wcf: 458,05 ms.
WCF NetTcpBinding done. Avg : 475,05
Remoting: 35,00 ms.
Remoting: 58,01 ms.
Remoting: 35,00 ms.
Remoting: 35,00 ms.
Remoting: 34,00 ms.
Remoting done. Avg : 39,40