Everything can be done, you can invest a lot of time to make your code run better on JVM and tune the GC settings etc. If you make the same investment into the Erlang ecosystem (like for example WhatsApp guys did) I think you could match the JVM performance in terms of handling number of connections and staying responsive. If your code does numeric calculation most of the time you are probably having a better time on the JVM though.

http://www.erlang-factory.com/upload/presentations/558/efsf2...