MrRipley gave an excellent answer to the question. Here's a little something more to think about: RAM recommendations are just what the name says. There's minimum requirements and recommended requirements, both of which are quite general. At one time someone said that doubling the amount of the recommended requirement would be golden and I believe that is still valid advice. Also bear in mind, that Windows itself is using RAM all of the time, so if the game recommends 2 GB, doubling that would be 4 GB and with the amount of Windows' usage you'd be counting to 6 GB. Thus 8 GB would be a nice amount to have in a modern 64 bit Windows system.