My D5100 suffers a bit from "stuttery" video too sometimes, but only in videos where something passes at speed close by, like a car or train. It's like the subject moves a short distance between samples, so its movement isn't fluid. I have all of the settings made to avoid this and I have a fast card in the camera. I'm guessing that the camera's sampling rate isn't fast enough. It's not a big deal because I don't often shoot videos, but it's distracting. I run an i5 laptop with plenty of memory.
I've not thought about looking at the video using the camera's screen to see what it shows. Good idea LensWork.