Default cost variables in postgresql.conf

Hi:

Are the "cost" variables (e.g.
random_page_cost,cpu_tuple_cost,cpu_index_tuple_cost)
in postgresql.conf optimal for a particular set of
platform / hardware requirements? (i.e. the configs
works best for let say if you have PIII computer w/
IDE as storage).

I'm asking this since a lot of softwares' configs
are defaulted to a "conservative" settings where
allowances are given for people who have older/slower
CPUs(w/ not so large amount of memory).

Thank you in advance.

ludwig.

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