Hibernate 3.x vs. performance perspective 4.x

Question

Are there any performance differences between hibernate 3.x and 4.x? and what is recommended to use (I mean hibernate 4.x is stable)

Answer 1

Since Hibernate 4.x was released some time ago (2011), it can be considered stable.

This question asks about new / improvements in Hibernate 4 and this site compares versions 3 and 4 with the improvements made in each version.