Gpu for dual 1440p

Hi all,

I currently upgraded to a qnix 1440p 27" screen, and my 2x hd6870 cf are a little weak for gaming.

I would like to upgrade the GPUs with the possibility to add another 1440p screen in mind. I would game on one screen but use the 2 screens for everything else.

It would be better to buy 2 hd7950 for cf (they can be purchased for less than 200 each) or would a single hd7970 or gtx770 do the job? I don't want to spend more than ~400.

Thanks!

 

the 770 would be ok but the 780 and titan are the best for 1440p