I think you are going about this backwards. First, figure out which software you will be using for video editing and 3d modeling. Some may use CUDA cores, some may use Opencl. Then you need to find out how much that software uses the videocard for. Some programs may use the videocard for everything, some may only use the card for certain parts of the task. Lastly, find out from people who use that software, usually at the forums for that software, if a videocard even makes a difference.
After you do that, then you'll have an idea of what card, if any, you need. It's not something where people can just say "Yes that 730 will work" or "No, that 730 won't work".