Pokertracker/postgres/600000 hands --- 2GB or 4GB RAM?

[flite]

I'm actually buying a new computer and since 2GB RAM cost less than the average visit at Burger King, my question is: 2GB or 4GB?

The computer mainly hosts poker software and a 600000 hand postgres database. do you think 4gb would make it run faster?

beside of that: does raid0 make PT/postgres faster?

thanks and cheers.