How much Watt needs a Quad ATI Radeon R9 290 CrossFire?

[aleejj]

I'm right thinking about expanding my mining (Lite/Doge others) PC.

So how much amount of Watt will I need for those cards?

And eh, do I also need to upgrade my RAM, I currently got 4GB 1333 DDR3..Is it enough?

 

[Rams Anirudh]

EVGA SuperNova 1300 watts is good enough to powerup 4 x R9 290