Almost a year ago now, I grabbed a cheap GT430, it’s an OpenGL 4 and has OpenCL/CUDA capabilities…and I haven’t had any DS problems with it…Newegg has the same model (the 1 GB version) for $40 right now. I do a lot of stuff in Blender and use the GPU rendering in the Cycles render engine, along with playing around with Luxrender.
I think most if not all the problem IS the card…and while you may not get the ‘jaggies’, using the onboard video is going to eat into your system RAM, too…so if that is 4 GB or less you chance running into out of memory conditions for DS.
But a couple of other things…go into to Nvidia controls and make sure that everything is set to the ‘application’...AA. anistropic and so on. Also over-ride the refresh rate and ‘unlock’ it…