MasterMace :
If you're using 2 x R9 290x's, 850w won't be big enough. if you're looking at R9-290s, I couldn't tell you, because it's not out.
incorrect, the r9-290
X can only draw 300W of power MAX without an add on power board like some of those extreme overclockers use with the titan to shove hundreds of Watts more down it's gullet. The 8 pin and 6 pin connectors will give you a combined max power draw of 225W, the PCI-E slot will give the card 75W for a combined max power draw of 300W under the absolute max overclock you can stick on it. a Stock r9-290X will draw around 200W under load
An intel i7-4770k under a heavy overclock won't draw more then 180W... ever.. basically his system draw will be around 600W-850W depending on the overclocks achieved. Of course that's assuming xfire. His build has nothing to do with xfire or the 290x
FlyingHelmet-1373206 :
It was the 290 (no X) i was looking at, any other thoughts?
A single 290 will probably draw less power then the 290X... so your psu should be overkill even if you are building with xfire in mind down the road.
That said i don't trust that psu manufacturer. Get yourself a Corsair, Antec, XFX or Seasonic... generally seasonic makes the best psus... and a good portion of the corsair, antec and xfx lineup are just rebranded seasonic psus (even the psus which are not rebrands tend to be fairly dependable from those manufacturers)
You might want one that is "haswell ready", you can use any PSU with haswell, it's just only some will support the low power modes the cpu will want to use. Those haswell ready cpus all will support those low power modes.
only thing missing is a cpu cooler. that's an overclocker's motherboard, i assume you plan to overclock, so you'll need a better cpu cooling solution.