it just makes the pic bigger. you can go full screen with anything in media player or even you tube for that matter.
Yes, I know it makes "just" makes the picture bigger. However, it still takes more processing power to drive. Instead of updating 786432 (1024x768) pixels every frame you are updating 2304000 (1920x1200) pixels. If you try to watch flash video (pretty much anything online) at fullscreen on my x1600 it will lag, however youtube HD (non-fullscreen) works flawlessly.