Unfortunately the graphics cards on a Dell latitude e6400 cannot be updated, your only options are to make sure your using the latest drivers to get the most of it, apart from that you can only replace the laptop with one that has a better dedicated memory type of graphics card.
Unfortunately the graphics cards on a Dell latitude e6400 cannot be updated, your only options are to make sure your using the latest drivers to get the most of it, apart from that you can only replace the laptop with one that has a better dedicated memory type of graphics card.