I came across this document:

http://www.firebirdsql.org/file/documentation/papers_presentations/html/paper-fbent-impacting.html

It seems to be talking about a much older version of FB than is available now. Even back in the days of Win 2003 Server, I've built systems that had probably 300 concurrent users without performance degradation.

I intend to connect about 2000 concurrent users. Is the subject FB version capable on say, 16GB ram, assuming I have a very simple and efficient table structure, queries, plans, FKs and PKs?

If FB cannot handle this number of concurrent connections, what DB should I move to? MS SQL or Oracle? or something else?