Apple seems to hate supporting old hardware. There have been several things that have bothered me when trying to upgrade Mac systems: Note that much of this page is for older video cards: AGP-based for PowerPC systems. My model of Radeon HD5870 is the 'Built by AMD' reference design. It came with an ATI Radeon X1900 card, and I was able to flash one of my old AMD Radeon HD5870 cards for use in it. This is one of the systems that Apple abandoned way too soon.
I recently got an Intel-based Mac Pro (MacPro2,1).
