I have a lot of experience with Engineering CAD software, while I do not use Solidworks regularly, I am Professionally certified on Autodesk Inventor Professional (which is the same thing). Both Autodesk and Solidworks software are geared towards Nvidia GPU's, they do in fact use CUDA. The main difference is the drivers. Nvidia drivers especially the Quadro cards drivers are designed for CAD and other professional software. I have used the 5870 with Inventor, and have found that it is decent, but I recently upgraded to the Nvidia Quadro 4000 and let me tell you I have never seen this kind of performance. ATI cards and Geforce cards are designed to keep frame rates up during gaming, while Nvidia Quadro cards are geared towards stability and accuracy.