Windows 7 + ATI + Stuttering Output

This applies to Windows 7 and MXWendler version 5.0+ and with ATI/AMD graphics

Problem

You have an output window that fits exactly the output device and video output is stuttering:

Test

1. Create output window without window decoration and exact position and size of secondary output.
2. Open MXW, play video. The video out stutters when playing video.

Solution

1. Create a display group using the Catalyst Control Center.
2. Display group must contain primary and secondary monitor.
OR
3. Make output window eg. 1 pixel larger than needed, eg. 1921x1080 for Full HD.

Background

ATI/AMD interprets accelerated fullscreen windows as games and changes the display swap timing to achieve minimal latency times which are important for games. This cannot be turned off separately.

Note that NVidia systems may be affected, too.