Cuda cores are not the same as stream processors.
Just pointed out that, and it's a fact, also i just suggested than both are not good enough for gaming even at 720p, he'll better off saving for a 7750 at least or 6670.
Go for the HD 6570 I Had both ( I only play league of legends and dota 2) gt 610 was my first gpu. the HD6570 can play league of legends and dota 2 at 1920x1080 and having 70-80 fps. i can even go beyond that with overclocking it using amd catalyst