Please disregard. Didn't solve my problem, just got a different card. Easiest solution to video card issues. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A friend of mine sold me his old XFX Radeon 5770 which I (think) I have successfully flashed. It works fine in my old X38 tower, and I am (or uh, WAS) able to boot it with a DOS disc in my 1,1, but now every time I power the machine on with it installed, it just seems to short out. Power supply issue? The machine works fine with another GPU installed, but the 5770 would be ideal if I could use that. I've tried swapping 6 pin headers and cables, doesn't seem to be the issue. I'm also not getting an EFI boot screen, but whether that's the card, or the short, or a failed flash, or the fact that I'm using an old acrylic Cinema Display is up in the air. Any help is appreciated. Thanks. EDIT: Not sure it's a short. It just powers itself off suddenly. I don't get anything on the screen, although I'm not sure if there's a difference between the 32bit EFI on the 1,1 and the ROM I used to flash the 5770, or if Piker-Alpha's boot.efi for Yosemite has any play on this. Currently booting Yosemite 10.10.1 on my 1,1 with a PC Geforce 405 no problem. It only seems to "Short" when I try to boot OS X. EDIT 2: Seems to be an issue with my tower unrelated to the GPU. Disregard this topic, I feel there are deeper issues at hand here rather than just a GPU problem. I'll update when I can get the machine to boot again.