Hopefully this is the place where I will get my answers. I have been struggling to get decent viewport performance with different 3D animation applications for about a period of 6 years now. I have recently started using DAZ 3D and want to upgrade my video card which is quite old GTX 460 however before I do so I want to make an informed decision before I buy versus the last time when I blew 500 euros on a completely unnecessary card that made absolutely no difference. The problem I am having is sluggish viewport performance when I build a moderate kind of scene with say a couple of buildings and a car and a person. With this kind of scene the 3D animation software becomes all but unuseable. Sluggish to a point where I cannot work anymore on the project. So. My questions are:

- does openGL use in anyway the cuda cores on a GPU? I suspect it does not but I would like to be sure and hear it from an expert.
- does the 3D application have to be designed to support a particular version of openGL? or will the same version of 3D application fully utilize each newer version/release of openGL and/or video cards?
- how important is the amount of video RAM with regards to openGL performance? Can sluggish behaviour mean that the cards memory is being overtaxed by the loaded scene?
- In terms of openGL/viewport performance in a given 3D application, will a cheap video card with say 2 GB RAM and openGL 4.4 perform exactly the same as a much more expensive video card with the same RAM and openGL version? does it make any difference?