I bought a MP with the default video card (GeForce 7300 GT) last september and just started noticing intermittent video-related issues. Approximately 2 times in the last 7-10 days I started noticing these thin blue horizontal lines flicker across my 24" Acer screen. The first time I switched the DVI connection to the other port and it solved the problem for a couple of days. The second time, I switched the DVI connection back to the other port and haven't seen an issue in about 2 days. Has anyone had this happen to them? Is the video card going or is it my monitor? I'm covered under AppleCare so I trust if I bring it in they'll fix or replace the card. Does anyone know if I want to upgrade the card whether Apple will credit me the difference between the 7300 GT and the ATI card? I think on the BYO store the difference is a $249 bump.