[Damien]

We have multiple BB servers, these servers are running all the BB services.

Should we have an advantage when installing an additional server with only the attachment and router service running and remove these services from the other BB servers ?

BB 4.0 SP2, 600 users/server, 3 servers

[BBTechGuy]

The Router Server is a low usage Service so I don't think you'd see a lot of gain there. The Attachment Service possibly could be beneficial depending on your user's usage patterns such as size of attachments and frequency of retrieivng new attachments.