Hi Tim,
1) I’d try setting the CompositionHost.SearchPatterns (in your global.asax?)
While this affects initial startup, it wouldn’t necessarily be the cause of problems as each EM is constructed.However, if the list of probed assemblies is large, that might cause later performance issues.
2) Also, have in mind that in n-tier every EM will be doing initialization and handshake logic to talk to the EntityServer, overhead that could be avoided if communication with a BOS on another server is not really necessary.
3) Every EM will also try to login before anything else is done with it, so you might want to take a look at your IEntityLoginManager logic.
4) Check your debug log. It might show the areas that are taking the longest and help you diagnostic the problem.