cpu ?

i was reading the specs for pc of th game and while i have basicly everything its needs to run, one thing pop out me the cpu need for xp its 1.3 and for vista its 2.4. that large jump. why idea why such a large jump between them, then also leads me to ask are they talking about this back to which processor level. p4, celron, etc.
i'm using a am 64x2 dual core 3800+ which is 2.0 ghz.
i dont think there talking about it being vista 2.4 am dual core, there talking about older one, but if they are talking my level this, boy that's steep and and upgrade for some that wwould have to be made, including me. specs where written better in the past meaning they say p4, celron,, etc, you get the pont for software, nw its just the spped not the processor level.

CPU - 1.3 GHz or faster (2.4 GHz for Vista)

Vista uses more memory.

i know the memory is 2x that of xp, but that doest expian the cpu increase. the increase of cpu sped. a little jump is expected, but that much? your aslo not answering the other part of ? and that is are we talking about the level min processor being p4, , celron, athern, seporn, etc.