I would disagree with the above post; the 650Ti is just as fast as a Nvidia GTX560, which I am almost 100% positive is the recommended card on the system requirements list for BF3.
You might just want to lower the settings though. Your card should be able to handle it on high. I was able to handle it on high with my slower GTX460 256-bit with my AMD 965BE. Both of which are slower than what you have currently.