agreed, when there are no games to be played there is nothing to challenge the modern graphics card. video memory is mainly used by games to generate textures, 3d models, scene geometry etc. when you are just using ms apps and the like, your video memory can be calculated by using the colour depth *number of pixels on the screen e.g.
(number of pixels 1024*768=786432)
(786432*32bit colour depth=25165824)
it probably uses a bit more than this at all times but it still goes to show that you dont need the latest thing out if you are not playing games.
btw sorry for any poor maths, i think its alright