Graphic Cards for Resolve - 2 needed?

Hello,
I just ordered a GTX 680 with 4 GB Ram for my i7 930 1366 Plattform PC.
That goes together with my GTX 460 1GB OC from Gigabyte.
Does that combination work? Or is it better to have only the GTX 680 to avoid problems.
How to select which Graphic Card is for the Interface?
I will also work in CS6 Cloud Aftereffects and Premiere.
Thanks.
I just ordered a GTX 680 with 4 GB Ram for my i7 930 1366 Plattform PC.
That goes together with my GTX 460 1GB OC from Gigabyte.
Does that combination work? Or is it better to have only the GTX 680 to avoid problems.
How to select which Graphic Card is for the Interface?
I will also work in CS6 Cloud Aftereffects and Premiere.
Thanks.