I find your sentiment about ORM overhead spot on. I did a simple unscientific benchmark once that showed a 2x overhead using jdbc versus a native driver and a minimum 4x overhead using hibernate vs jdbc. That means that using hibernate proved to be 8 times slower than using a native driver! And this is before you get into issues most ORMs have struggled with like efficient joins. And as bad as hibernate is, dynamic language ORMs are even slower.