As a general rule of thumb, given an nVidia graphics card of the model designation XNN (420, 570, 680, etc.), NN should be 50 or greater to be considered adequate for graphics-intensive gaming; lower values are typically meant for web browsing and video playback. (X inidcates the generation of the chipset, NN indicates the performance within that generation.) The same generally applies for the older XNNN series of nVidia cards.