Your "benchmarks" are flawed. Perhaps look at pgbench, sql-bench and tpc for standarized benchmarks that have been tuned over years (some of them over decades)

Your "benchmarks" are flawed. Perhaps look at pgbench, sql-bench and tpc for standarized benchmarks that have been tuned over years (some of them over decades) to provide meaningful results. Whatever it is you are measuring there (with apachebench, seriously?), it's not the database.