Hey there, I bought a used cMP 4,1 from eBay and it came with a GTX 780 Graphics Card. I don't hear the chime, it takes a minute or two before OS X starts to boot but I see the grey screen, apple logo and loading bar before it gets to the login. When I go to the settings I see 2.5GT/s Link Speed (which I read was just a cosmetic thing). Does this mean it's an EFI Flashed Card? The reason why I ask is I'm trying to flash my firmware to get from 4,1 to 5,1 and I don't have the original Video card so I want to make sure I won't make my Mac Pro unusable. Thanks! UPDATE: After great advice from ActionableMango to tell me to hold down Option to see it turns out I do have an EFI Certified GTX 780. Thanks again man!