PC (RPG) Extended Preview = 05 Guild Wars : Prophecies [TrueHD][HDmax]
This video is for watching in full-screen. You can watch at HD video quality without even using the HD button! The advantage of this is; it may run smoother and take less CPU than if you were using regular HD...
Disadvantage is, it takes about 5 minutes to load the video! (Due to much larger size than normal)
If you use turn on HD however... you'll be using HDmax, which is basically the same quality as the original file...