Win XP 64-bit has the capacity to work a lot faster, sort of like a large
diameter drain can drain your swimming pool faster. However, this capacity
can only be realized if your hardware is up to the task. The new 512Mb cache
memory CPU's are up to the task. With a lesser cache, you may not be able to
achieve the software's potential, just as if your swimming pool drain were
connected to a small-diameter sewer pipe. The benefits of 64-bit are really
only seen under demanding conditions, but, in the future, processing demands
are bound to "rise to the occasion," so to speak, and 64-bit will become the
norm.