Different socket connections or namespace in socket.io?

I need to have different channels for my Socket.IO implementation. These different channels will have different processing and different data will be passed to the clients connected to different channels. I am a bit confused whether to use different socket connections as in i guess i would have to create different connections on different ports? or to use the standard namespace functionality that socket.io provides. My main concern is that if i choose namespaces it will use one socket connection for all the channels, so will the performance of sending data across to lots of clients on different channels be affected because of it?

Any suggestions or inputs are highly appreciated. Thanks