Video playback skipping on Velociraptor 300gb

So I have just recently noticed when playing any video regardless of the media player the drive seems to start skipping. This last for about 30 seconds then video playback will go back to normal. It seems to almost be like clockwork when watching a movie as far as time between thisskipping issues. Seems to be about 15 minute intervals. Any help n what I can do to resolve this would be much appreciated.

Does that happens with all your video files or with a specific files type?

and were they working fine before, recently?  and did this start after a firmware update?