Great to hear you're planning to do some Postgres benchmarks!
To improve fairness, you might want to consider using pgbouncer (setup to only offer simple session pooling) in between the Postgres db and any framework that doesn't have internal support for connection pooling.
E.g. I'd love to see how Flask performs using just the psycopg2 driver (i.e. raw db access, no ORM) and pgbouncer to handle the pooling.
