Nvidia 8600GT 256MB

I've installed Ideneb and it's going smooth but when i move, resize, scroll down windows it suddenly reflects/flips the content of the window upside down. It's strange but graphic accelration is enabled and quartz is (disabled quartz) but it doesn't change anything.

a) How do I disbale graphic acceleration?
b) Do you know how to fix it?

Thanks

[Updated] Screen Shots

Artifact Screenshothttp://i44.tinypic.com/2dqj440.jpg
Graphics Card ~ System Info : http://i42.tinypic.com/5po60l.jpg
Finder Artifact Example : http://i39.tinypic.com/288y1qt.jpg