Best combo for display and rendering

Hi all,

here is my setup from 2009 :

  • i7 980x
  • 24 Gb de RAM
  • GTX 580 3 Gb for display
  • GTX 780 6Gb for rendering

My GTX 580 used for display is dead. I took an other GTX 580 which is in an other PC used for gaming (I play a few times a month) to replace the dead one but now, I need a graphic card. I come with 3 solutions :

1- keep my GTX 780 for rendering and buy an other graphic card for display. A card which can handle a lot more of polygons than my GTX 580 (so the change really makes a difference)
2- take my GTX 780 for display and buy a new card for rendering, but which one ?
3- use my GTX 780 for the gaming PC, keep my 580 as spare and buy 2 new graphic card, one for display, one for rendering and in this case, what’s the best combo ? I want to be able to use a 4K display as I plan to buy one before the end of the year.

So the final question is the title of the topic :D.

Thanks for advices.

I would go for option #2, get the best card your budget will allow. Start looking at the Nvidia 10 series cards to start with (1060, 1070, 1080, 1080ti).