im currently shopping for a new mac im leaning toward a refurbished mac pro 2.0 ghz quad which is 1899US does anybody have the 2.0 ghz mac pro? if so what's it like so far speed/performance wise my dad has the 2.66 and its blazing i want to know if the 2.0 ghz is that much difference its a 660 mhz decrease on each CPU