I tried out the four test videos on Windows 7 Home Premium-64 Bit. I used Windows Media Player and VLC. All the videos ran perfectly smooth except for the .WMV test video which stuttered slightly on Windows Media Player. It wasn't a game-breaker, but still noticeable if one was looking for it. As far as I know, I have stock codecs as in I haven't installed anything crazy like CCCP or K-Whatever.