Please don't start a flame war over this. It is meant as more of a Dilbert-style post with just the slightest bit of real technical content.
64-bit machines are twice as fast as 32-bit machines because they have more bits.
Believe it or not there are still some people inside and outside Microsoft that believe this. They're probably the same folks that believe a 4GHz P4 is twice as fast as a 2GHz P4. Wouldn't it be nice if all that was really true?
I really do love my 64-bit machines. One of them I run with a 32-bit OS, the other with a 64-bit OS. They're both really fast at real world developer tasks despite their seemingly slow clocks. They're not twice as fast, but they might be if you figure out a way to factor in their inherent disadvantage: all the pointers are twice as big. Depending on your data structures, that could be a pretty big disadvantage.