NBA? I'm pretty sure that game will be played smoothly with 5650M better than 5470M, just like Maziar said above.
Still, NBA is a 3D games that need some horsepower. You'll better with 5650M.
Well,it depends on the resolution too.
5470M can handle NBA fine;however,since it's not overall a great card for gaming, you may need to lower the res/settings