I have read hundreds of posts regarding problems with the 23" Apple Cinema Display, but I have not seen anyone with the problem I am having, so I am hoping someone can help. I had a 23" display hooked to a G5 at my office. It worked fine for a few weeks, then I got a line that appeared across the screen, so since it was still new, I was able to return it to Apple for a new one. I got my new monitor and it worked flawlessly for about 8 months. I left for a week for vacation and when I returned my monitor was completely dead. I took it to an Apple store and was pleasantly surprised when they gave me a brand new monitor. This is where my latest problem started and what I can't seem to figure out.... I plug in my new display and within five minutes, the display is flickering so much that it is like watching at a strobe light. I am pretty sure that it is not a problem with the display, so I begin swapping out monitors on some of the computers in my office and the new monitor works perfectly on all other machines. I also plug in another 23" display from another machine and it begins flickering the same way. In the meantime (in order to get a little work done) I order a 20" display and it works fine. I troubleshoot for a week and adjust refresh rates, reset the PRAM, and try other things to see if the 23" will work on my computer and I decide to order a new video card - hoping that this will solve my problem. My new video card came in yesterday, and I am still having the same major flickering/strobing problem. Has anyone ever heard of anything like this? Why would a 20" Apple Cinema Display work fine and the 23" will start flickering immediately. Any suggestions would be greatly appreciated, as it breaks my heart to have to work on a smaller display when a nice 23" is sitting unused right behind it! Could it be some sort of electromagnetic problem (I've moved away my speakers, iPhone, iPod and external drives away from where the monitor sits, but that did nothing to help). If it is in fact a problem with the G5, what could it be and can it be fixed?? Any help would be greatly appreciated!! Thanks!!