vsync question

[marylandman]

so I have a question that may have been asked a thousand times but,
Vsync as it relates to LCD screens. I've read somewhere that with LCD's the pixels change as needed and not the way a CRT does a refresh. Why do LCD's still exhibit tearing the way CRT's do? Is it because video cards still output the way they did during the CRT era? Because I dont understand why tearing would appearing identical on an LCD as it does on a CRT unless the gpu output is at fault.

 

[Christopher]

The video card still sends a complete frame at the refresh rate interval. Tearing happens when the frame being sent to the display is updated mid-transfer via the video card. Vsync eliminates that by syncronizing the frame updates of both the video card and the display.

 

[Ankle]

Anand's article about triple buffering and vsync may be of some interest to you: http://www.anandtech.com/video/showdoc.aspx?i=3591