freebsd performance

Hi all,

I try to find OS with better performance.
At the mement we are using linux RH AS 3.0 and I think it is not the
best possible.

So my test server:
Dual Pentium III 1 GHz
1.5 GB ram
30 GB ATA 7200 HDD.
pg 7.4.2

I installed freebsd 5.2.1 (It is my first try on it).
and ran the same db and pg setup.
So I see 30% slower freebsd box compared to linux RH.

My question:
exists any special setups into freebsd to get it running faster?
Also any good docs about configuring freebsd for postgresql will helpfull .

regards,
ivan.