AFAICT pgsql controls this with the random_page_cost and seq_page_cost variables [1], which are relative and seem to default to 4 and 1 respectively. It doesn't look like these are automatically adjusted though based on the hardware.

Some searching and I found some blog posts suggesting lowering them both to closer to one on SSDs [2]. Indeed, the documentation says you can set them both to 1 if you are sure that the database will be fully cached in RAM.

[1] http://www.postgresql.org/docs/current/static/runtime-config... [2] http://www.cybertec.at/2013/01/better-postgresql-performance...