Slow SELECT on three or more clients

Hi!

Im new to PostgreSQL.

My current project uses PostgreSQL 7.3.4.

the problem is like this:

I have a table with 94 fields and a select with only one resultset in only
one client consumes about 0.86 seconds.
The client executes three 'select' statements to perform the task which
consumes 2.58 seconds.
With only one client this is acceptable, but the real problem is as i add
more clients, it goes more and more slower.

for a single select with one field in one resultset, is 0.86 seconds normal?

I tried vacuuming and reindexing but to no avail.
the total record count in that particular table is 456,541.

Thanks in advance.