6750 m kaart

Performance levels depends on the resolution at which you'll be playing.However a 550Ti or HD6770 can be considered as the bare minimum necessity for good quality or Hi-fi gaming.

What game are you planing to play?

The 6750m is a fast middle class laptop gpu. Will play most modern game in medium setting.

But you don't want to get a Mac if your game is only available on Window.