You are watching a video in Microsoft Windows Media Player 11 in Windows Vista. When you move the Windows Media Player window by using a drag operation, the video performance may suddenly be reduced. For example, you may notice lost frames or other poor video performance. Video performance decreases only while you move the window. When you stop moving the window, the video plays as expected.

This problem occurs if the following conditions are true:

• The system supports Windows Aero. However, Windows Aero is turned off. This problem does not occur when Windows Aero is turned on.
• The screen has been rotated by using a third-party display rotation utility. This problem does not occur when the screen has not been rotated.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

The problem may be more severe on computers that have slower CPU hardware. The following factors may also affect this problem:

• Display resolution
• Random access memory (RAM)
• The graphics processing unit
• The memory bus
• Drivers