Was thinking about what PCI ports Macs use. In particular, aluminum iMacs (the current gen, one before it and one before that). I know it's some custom Apple PCI port, but was wondering if you could nab a surplus graphics card that might fit it. (If you wanted a better card than the one you have, but that card was not in your computer, BUT it is made by Apple for a better version). also, do the PCI ports change per generation? I was guessing that's too much work on the part of Apple/ATI. So tl;dr: what PCI slot do Macs use?