[darkphantom]

Originally Posted by anmcguire

I'm not sure how you came up with that number... A 32 bit register can address up to 4GB of RAM directly (or the maximum size of an unsigned int):

bash-3.2$ perl -le 'print 2**32'
4294967296

64-bit architectures offer other advantages as well, including faster processing for some tasks.

here ya go

For example, the System Information dialog box may report 3,120 megabytes (MB) of system memory on a computer that has 4 GB of memory installed (4,096 MB)....If a computer has many installed devices, the available memory may be reduced to 3 GB or less. However, the maximum memory available in 32-bit versions of Windows Vista is typically 3.12 GB.

http://support.microsoft.com/kb/929605