By default, Silverlight will auto-detect your buffer settings and adjust playback based on your Internet connection. You can also set this manually and force a certain buffer rate if Silverlight is not adjusting it properly for you.
1. Open video you would like to watch and press pause.
2. Click once in the middle of video
3. Press Ctrl+Alt+Shift+S
4. Click Manual selection and select higher buffer rate and click apply. Pick 3,000 for full HD
5. Wait until you have loaded enough buffer .
6. Click play to resume your video. You will notice HD icon.