High Processor consumption

I am running RH 7.3 running Apache 1.3.27-2 and PostgreSQL 7.2.3-5.73.
When having 100+ users connected to my server I notice that postmaster
consumes up wards of 90% of the processor and I hardly am higher than
10% idle. I did notice that when I kill apache and postmaster that my
idle processor percentage goes to 95% or higher. I am looking on ways
that I can find what connections are making the database processes run
so high. If this could also tell which program is accessing it, it would
be helpful. I have look through the documents on performance tuning
postgresql and have adjusted my memory with little effect. I have even
routed all traffic away from the Apache server so no load is on apache.
I do have C programs that run and access the database. Any help will be
greatly appreciated.

Thanks in advance,
Ben