Pat Cassity , Dec 31, 2012; 01:19 p.m.
The card will make no difference. The only way to reduce 'rolling shutter artifacts' is to use the highest frame rate possible. Unfortunately the D800 only offers 60fps with its 720p format. If your videos are not going to be viewed on a large screen, you probably won't notice a difference between 720p and 1080p. 30fps (in the 1080p mode) will pretty much eliminate it as well since you can't use a shutter speed less than 1/30. I would have thought that Nikon would have made 1080p with 60fps available on the D600 and the D800.