It can probably run Diablo 3 at its native 1280x768 resolution, on low or medium setting at 30fps. That's good enough to be playable, but if it is smooth or not is up to you. To see how the 6620G video card of that laptop performs, see this video http://www.youtube.com/watch?v=Lo_Av_TAHtM (that video is running on a 1600x900 resolution laptop and I think he`s getting 24fps on high).