I upgraded to Tiger (10.4.2) over the weekend from 10.3.9, and now the display on my 17" Studio Display shakes and briefly changes color (flashes light). This starts out just happening every 10-15 seconds, but after the computer has been on for a while it's just about constant. Occasionally the screen flashes black for a couple of seconds as well. For some reason it's particulary inclined to go black when I drop a new widget on the dashboard and the ripple animation is finishing up, but it happens other times as well. I have an ATI 9800 (4x AGP w/ 128mb) running to an Apple DVI to ADC adapter. This never happened under Panther. As far as I know I'm running all the latest ATI software (ATI displays 4.5.1) and current firmware (has there been an update since October '04- that's the most recent one I can find.) Any advice would be greatly appreciated as this is driving me nuts. Thanks for your help!