I've decided to upgrade my PC and I'll be making the jump to QHD. I planned on getting a I7 4930k and a SSD but I'm at a loss with what to do about video cards. I currently have a 780 3GB would like to go SLI. I'd like advice on whether or not to add a second 780 3GB or sell my current card and get two 780 6GB. Any thoughts would be greatly appreciated.