postgres performance

Hi,

I have installed PostgreSQL6.2.1 from my own user account (I was just trying
to test out something first). It seems to be running too slow. For example,
the self join of a table with roughly 300K records takes 2-3 hours. There is
an index on the join attribute.
I am running it on a 8 processor (each is a 248 MHz SUNW,UltraSPARC-II)
 machine with a total of 2.0 GB main memory.
But, since it is not parallelized, it may get the power of only one processor.

Does it make a difference in performance since I have installed it from my
user account, and not the root. Also, I compiled it using gcc on a
solaris 2.5 machine and the machine I ran it is a solaris 2.6 machine. I did
that since the solaris 2.6 machine is the fastest we have here and the
executable
compiled on 2.5 was running properly also. Can that have an impact on the
performance?

Thanks
--shiby