I'd say a good quality 350W PSU with around 18A on the 12v rail would be recommended. Yes, low power could stop the machine from booting.
Originally Posted by thenutty1
Hey I'm back again attempting another build with the same video card from the other night. My question is, how many amps does a 6600 need on the 12v rail? If it doesn't have enough power, could that be causing the card to not display anything (even during POST)?