CPU killer

Greetings,

    I've been using Postgres in a Pentium 75Mhz, Linux RedHat 6.2, 32Mb.

   Every big query I execute uses too much cpu (more than 90%).

   I start postgres with these params: su -l postgres -c
'/usr/bin/postmaster -B 2048  -i -D "/home/postgres/data"' &.

What should I do for avoid postgres extreme cpu allocation? I know sometimes
non-indexed tables or huge size tables can be slow, but here I don't care
about execution speed, I just want less cpu allocation no matter how slow.

Regards from Brazil,

José Vilson de Mello de Farias
Dígitro Tecnologia Ltda.