Different Approaches
Most applications in Snow Leopard run in 64-bit mode. Occasionally, some, such as System Preferences, start in 64-bit and have to restart in 32-bit for compatibility. Apple has clearly positioned 64-bit as the new norm, and 32-bit as a legacy implementation.
On Windows, 64-bit applications are labeled as such. For example, the icon for Internet Explorer is labeled
Internet Explorer (64-bit). Special attention is called to the fact that unlike most of the rest of the applications, this one is 64-bit.
Both approaches create some confusion for users, though the Microsoft approach is far more confusing. In either case, for 99% of users and 99% of applications (numbers pulled straight from the source of most statistics), 64-bit apps are pretty much meaningless. On any architecture other than x86, 64-bit apps are generally slower than their 32-bit equivalents, as it’s just an oddity (allowing access to additional registers on x86-64 systems when in 64-bit mode, IIRC) that allows 64-bit apps to be about the same speed or faster than 32-bit apps on Intel and AMD systems.
Oh well, at least this time, it’s better than the real mode/protected mode/386 enhanced mode stuff we had to deal with back in the Windows 3.0/3.1 days…
