>> Given the same physical hardware, which one is likely to perform better? Does >> it make any difference? Does using separate databases use more RAM than a >> single database with a bunch of different tables?
Config files are global, so I doubt it.
if it's a web app with persistent connections, then splitting onto several databases may consume more RAM. Example: 100 apache clients connected to 3 databases creates 300 forked postmaster processes ; vs 100 apache clients connected to the same DB using three schemas only takes 100 postmasters -- Vlad