R9 290 SLI or GTX 780Ti?

Either it seems to me is overkill for editing.
Those two setups are for fast action gaming.
If your editing app can use CUDA, then a midrange nvidia card like a GTX750 should do the job.

If your use is for gaming, you will win fps benchmarks with dual R9-290, but you will have a better/smoother experience with GTX780ti.