Makers of 290s recommend 700+ Watt power supplies. They do that for a reason.
And yet still hasn't learned to look up simple facts online.FYI: I have been in IT professionally since the late 1970s, probably about the time your parents were born.
Peak power consumption of the whole system is 440W.
![1382088059a47QS23bNQ_15_1.gif](http://www.hardocp.com/images/articles/1382088059a47QS23bNQ_15_1.gif)
And that's measured from the wall - AC current. Power supplies are rated with DC current, 440W from the wall translates to around 400W PSU requirement.