Which is better 32 bit or 64 bit

Squiz Matrix Installation
1

A quick question to see which would be the better os to install Matrix on


Red Hat 32 Bit



or



Red Hat 64 bit



Or it doesn't matter

2

PHP is 32-bit so it doesn't really matter for the webserver (though I'm sure a sysadmin will prove me wrong on this). 64-bit on Oracle servers is good, because you can get 64-bit versions of Oracle. I don't know what the impact on a PostgreSQL box is.
3

If you want to utilise lots of ram (i.e. more than 3gig), then you'll want 64-bit otherwise there is a performance loss when swapping out the memory mapping.