it all depends on what motherboard. the DFI lanParty series do not really work 100% with only 20pin. thats why a 480w or more psu with native 24 pin is recommended.
i have been reading this thead and from what i understand is that if you are not going to upgrade in 2 years a dual core would be nice. am i reading this right. i plan on building a 939 when the new socket comes out. cheaper is good.