How much RAM can I access with a 32-bit or 64-bit operating system?
Whether you use a 32-bit or 64-bit operating system depends on the amount of memory you require in the system. 64 bit operating systems, except for their access to more memory, do not provide improved performance, and sometimes there a problems finding 64 bit drivers.
Extra RAM also doesn’t help improve performance unless its needed i.e. you are running multiple memory intensive applications that are currenlty using up the physcial RAM. Once the system goes into using Virtual memory (hard disk) for storing the excess, it’s a 1000 times slower.-