I keep seeing different anecdotes about people having lagging issues with the Intel HD graphics card. Is it really that bad? It would be a real pain to have to keep it on the nVidia card all the time, even when unplugged. I'm afraid that it will really drain the battery a lot faster than having the Intel on. Anyone have any estimates of this? It's one of the more worrying things about the Pro. Can anyone help clarify this issue? Thanks.