I am using a 23 Inch Cinema Display and its just been returned from apple repair. Now when i plug the display into the 1st port on my video card i get some strange behavior. The screen displays the apple logo thru both loading screens. Once it hits the finder the display goes nuts. It turns off then on and sometimes displays circles or ovals in the corner of the screen. It feels like its struggling to put an image out. The on/off conitinues until i force shut down my powermac. Now when i plug the display into the second port of the video card it works perfect. Anyone have any idea whats going on?