I have a 2008 15" 2.4GHz unibody macbook pro with the Nvidia 9400 & 9600 GPU's. It works great, but i notice when playing 720p HD video in Quicktime X, the video is often kind of stuttery at first when i skip through the video, and sometimes beachballs. I am disappointed, because i often like to skip to certain parts in videos (especially TV Shows/Movies). It doesn't do this with smaller videos. I only have 2GB of RAM. Do you think upgrading the RAM to atleast 4GB would help with this problem? I am on the 9600 with the "Higher Performance" option. Do you notice this at all?