Hey all, First post on the forum... Have a Mac Pro 1,1 that I just upgraded the EFI Firmware on to 2,1. Have a couple questions I am hoping you can answer as I cant find these exact answers in the FAQ's... 1. I want to upgrade my Mac Pro to a GeForce GTX 660 Card. Can I do this? I am planning on upgrading the boot.efi and OSX to El Capitan as well, so I didntk now if the OS upgrade would allow me to use this Kepler card. Otherwise, I will have to look for a GTX 570 2. In terms of the El Capitan Upgrade, can I do it with the stock 7300 that is in the Mac currently? I am upgrading to 32 GB RAM as well, but dont know if I can do the upgrade with that card 3. Basically, which comes first, the chicken or the egg? The upgrade or the card installation? Or do I pretty much have to install a 570 first to be able to upgrade to El Capitan and give up on the 660? 4. What about AMD Cards? Anything worth it better than the two GTX I listed that I could use and be compatible? I have seen a video where a user installs a GTX 970 in a 1,1 Mac Pro, so that confused me even further!! Thanks for your assistance on this....confused on what exactly I can do.