Not trying to be argumentative, but IMO 2GB of video RAM is overkill for a GTX 560. The GPU's texture fill rate can't effectively keep up with that much texture data, so you're not going to see a performance increase. It might make it possible to use higher-resolution textures, mods that add a lot of per-zone assets, etc., but it's not going to make the game run faster. There's a reason that the reference spec for the GTX 560 has 1GB of video memory. Of course, if there's not much of a difference in price you might as well go for the 2GB version, but if that's not the case I personally wouldn't spend more for the 2GB version.