Howdy azalilboiz,
That would all depend on if you have a nice name brand Like Antec or Enermax etc.
Also what you are running. I know you want to overclock your video card. I would say yes. But if you have somthing Like persay me Amd 4000+ 4 gigs of
ram etc, you will need around 600 watts of nice pure power.
People always get hung up on watt's. Watts is a good thing to look for but you also want "pure current" as well a gerneric 400 watt
psu couldnt keep up with say an Antec True 300 because of the current it takes from your outlet.