I'm looking at purchasing a laptop. I have the option of the HD6870 or the GTX460M. There is also an option for a HD6970 card. The laptop will not come with a 3D bundle. What card would be the best between the HD6870 and GTX460M in terms of performance, heat, and power consumptions? What would be the advantage of selecting the HD6970 which is a 250 upgrade option? Also, are driver more available for one than the other.