Linux v.s. Mac OS-X Performance

Our developers run on MacBook Pros w/ 2G memory and our production
hardware is dual dual-Core Opterons w/ 8G memory running CentOS 5.  The
Macs perform common and complex Postgres operations in about half the
time of our unloaded production hardware.  We've compared configurations
and the production hardware is running a much bigger configuration and
faster disk.

What are we missing?  Is there a trick to making AMDs perform?  Does
Linux suck compared to BSD?


Thanks.