have u baught it yet or is this the psu u have a the moment?
it is fine for what u have. a few ppl have used this calculator but not sure how accuarate it is.
it reckons u need about 336w minimum.
http://www.extreme.outervision.com/PSUEngine
http://www.realhardtechx.com/index_archivos/Page447.htm
34A @ 12V, 2 x 6+2 PCIE connectors. Looks ok, but it will hit hard. I would tab 330-360W power consumption.