"You don't need a beast - as mentioned above, my ancient laptop (it's called Larry, by the way) has something known as a Radeon HD 6520G stuffed inside it, and it can just about deliver 30fps with all the settings on "Low". Definitely wouldn't want to go older/lamer than that, but the fact you're actually looking at 3-dimensional games on Steam makes me think you've probably already got that covered. But it is quite important that your graphics card supports DirectX 11. Things can get a little wonky on DX10."