As long as you have a CPU that can handle 64 bit operations and a computer compatible with that OS you will benefit. If i am not to wrong, Windows 7 works good at 1 GB of RAM so you should not have any problems. Your system will be a bit faster you can put in more than 3 GB of RAM, only problem might be that some 32 bit applications might have some problem running, so ill recommend using a 64 bit version of an application if you have that option. Other than that 1GB of RAM will not have any difference comparing to a 32 bit OS of the same sort.
-- INTEL 9xx SOLDIERS SANS FRONTIERS
