A good start:
Tuning: http://www.westnet.com/~gsmith/content/postgresql/pgbench-scaling.htm
Benchmark: http://edoceo.com/liber/db-postgresql-benchmark
Here's my benchmark on `m1.medium` instance of Amazon EC2:
http://gx.viettug.org/zen/kyanh/jobs/pgbench0.jpg.html
Anh,
Were you using a EBS device in EC2 for that benchmark?
-Greg
