When upgrading servers, you may encounter this question : Should we stay at at 32-bit OS, or 'upgrade' to a 64-bit OS?
To me, the big advantage of a 64-bit OS is the ability to address (use) more than 4 gigabytes of RAM. I sometimes bump into that limit on my desktop,
so I think it's best to have a 64 bit OS for servers.
Larger memory space isn't the only advantage, however. From Wikipedia :