For rendering, you'll want the extra cores. I would go 4830k if possible, 3930k if not. The 4820 borders on pointless because unless you need the PCI-e lanes or something, you might as well just get a 4770k and call it a day.
I would also probably not recommend the 780Ti for rendering work. Depending on what kind of applications you use, I would either suggest a Titan or Quatro/fire pro card if you need the double precision features, or if your apps support OpenCL, I would suggest something from AMD (R9 290, 280x, etc). If you can tell us what applications you use and what sort of stuff they support (cuda, openCL, etc.) we could help you more.
Thanx for the prompt reply.
Well, basically I will use this CPU as a back up, maybe light rendering. Nothing to heavy. since I've already got one with i7-4930K/Quadro K4000/Asus X79 Deluxe and G.SKILL Ripjaws Z Series 32GB (4 x 8GB)DDR3 2133.
I'm using Vray for Autocad 2013/3d max now(open to different rendering engine suggestions). The 3D rendering mostly for interior design/architectural designs. So, you think 780Ti+3930K is enough for light work? As for the heavy duty rendering I'll use the main CPU.
After reading your explanation, I'm leaning toward 3930K as the processor. But as for the Video card, I'm afraid I have to use it because unfortunately I've already bought it.
With the kind of work I'll use the CPU for, Rampage IV or P9X79 or Sabertooth X79?