[PERFORM] which dual-CPU hardware/OS is fastest for PostgreSQL?

I'm sorry if there's a URL out there answering this, but I couldn't find it. For those of us that need the best performance possible out of a dedicated dual-CPU PostgreSQL server, what is recommended? AMD64/Opteron or i386/Xeon? Linux or FreeBSD or _?_ I'm assuming hardware RAID 10 on 15k SCSI

[PERFORM] Benchmark two separate SELECTs versus one LEFT JOIN

Has anyone seen a benchmark on the speed difference between: SELECT * FROM item WHERE id=123; and SELECT * FROM vendor WHERE id=515; versus: SELECT * FROM item LEFT JOIN vendor ON item.vendor_id=vendor.id WHERE item.id=123; I only have a laptop here so I can't really benchmark properly. I'm h

[PERFORM] would number of fields in a table affect search-query time?

would the number of fields in a table significantly affect the search-query time? (meaning: less fields = much quicker response?) I have this database table of items with LOTS of properties per-item, that takes a LONG time to search. So as I was benchmarking it against SQLite, MySQL and some oth