With postgres you'll want to tune those cost paramters however. Eg: lowering the random page cost will change how the planner does things on some queries. But don't just blindly change it -- like modify the value and run the benchmark again. The point is that the SSD is not 10x the cost of RAM (0.1 vs 1.0). In our example a few queries the planner move to, what I always assumed was the slower sequential scan -- but it's only slower depending on your table size (how tall and how wide). I mean, PG works awesome w/o tweaking that stuff but if you've got a few days to play with these values it's quite educational.