Are WMV slow for you? Make sure you have DirectX Video Acceleration for WMV files enabled.
1. Open Windows Media Player
2. Press ALT on the keyboard to show the menu.
3. Choose Tools then Options
4. Click the "Performance" tab.
5. Check the "Turn on DirectX Video Acceleration for WMV file" option.
6. Press OK and close Windows Media Player.
I hope this helps some users with terrible WMV performance.