I have an iPhone 4, and within the past few months, video taken on that peripheral plays sluggishly (i.e., occasionally frame by frame) when I try to watch these uploaded videos on a Microsoft XP machine using Quicktime. I have recently updated Quicktime, and I backed the phone up to the computer, which has iTunes 10. Side issue I've been noticing is my computer won't allow me to download the updating drivers from Apple -- so I needed to transfer the Quicktime update file from a thumb drive after downloading on a separate computer. Is there any way to fix this frame by frame video playback? I don't have this issue in Windows 7 or on my actual phone.