Hey, I'm new to the forums and to macs. I'm having serious video card issues and everything I've read on the subject suggests that the card has heat sink issues and that a new card is required. I'm out of warranty and was just wondering if I had to go through the apple site to purchase a new card or could I just figure out what models are compatible with my mac and purchase one from a retailer or ebay? The card I'm using now is ATI Radeon X1900 XT and is PCIe bus. I'm using Mac OS X 10.4.11 and I have a mac pro that I purchased in 2007. If there's any additional information I need to post just let me know. Thanks!