Should I use a powered external drive?

Currently I am using a WD Passport external hd that is powered by the AppleTV. I frequently encounter stuttering playback during movies or tv shows that are synced to the external passport. Should I switch to a powered external hd or will I still get the occasional stutter regardless of which type of hd I use? USB 2.0 is fast enough to watch a Hi Def movie, right? Thank you in advance…

A full size drive will give you better performance, though a 2.5" (travel size) drive should be just fine for video playback. You may simply try swapping the USB cable. This has cleared up similar issues in the past some users were experiencing.