64bit CPUs

[Joseph Koshy]

> RAM/address space is the big reason.  In fact, applications 
> compiled for 64-bits may well run slower than 32-bit ones 
> running on the 64-bit kernel.

On the other hand we have 16 registers to play with on the AMD64
and they can be used far more orthogonally than on the i386.
That would cut down on the frequent register spills and reloads
that are the bane of the i386 and thus help improve performance.