Hmmm...
First, run top or some other program and try to figure out if either the AOLserver or Postgres process is CPU-bound.
Most likely (if you are CPU-bound) AOLserver will be the first to use up almost all CPU on the system - it won't use 100% because some of the time it will be waiting for info from Postgres.
Second, check Postgres tunables like max_fsm_relations, vacuum_mem and sort_mem, in addition to setting the shared buffers to be higher.
Third, if you really need performance turn off the fsync, which causes Postgres to flush the disk buffers after every transaction. I have done this on Solaris, which writes a transaction log for disk integrity anyways, with no problems. There is however the possibility of data loss should someone yank power to the system while in the middle of a transaction.
