It should be fine to play games at medium settings @ 1336x768 resolution.
My Lenovo Y470 has an i5-2410m and the nVidia GT 550m. It handled Crysis with medium settings with frame rates ranging between 35FPS and 45FPS most of the time. It would rarely dip down to 26FPS and rarely peak at 54FPS. With graphic settings set to high frame rates ranged from 18FPS to 24FPS most of the time.