Psu good enough for 290

*It sounds like you haven't bought the card yet?

If so, you might want to consider the MSI GTX970 TwinFrozr V.
http://www.guru3d.com/articles_pages/msi_geforce_gtx_970_gaming_review,27.html

The new Maxwell cards are amazing and also come with some new features you should read about if still on the fence. Here's the Asus performance as I don't have a good average of games for the MSI card (just increase it even more in the charts):
http://www.techpowerup.com/reviews/ASUS/GTX_970_STRIX_OC/25.html

So the MSI GTX970 is at least 15% faster than an R9-290X if you compare overclocked cards.