Just got myself a K3100M, but while researching this whole process I did come across early on someone that got an AMD card and flashed the card itself with the Apple GPU firmware and it worked. Just wondering if anyone did the same? I'd imagine it would work natively with this method instead of a VBIOS, but haven't really seen it mentioned anywhere.
www.ifixit.com
Also wondering if there's any benefit of AMD vs NVIDEA? I see majority (if not all) of the ones here (VBIOS) are for NVidea even though the one originally with the iMac is an AMD. Not sure if there's a reason for that?
SOLVED: What GPU's are compatible with iMac 27" 2011? - iMac Intel 27" EMC 2429
I used one of the Dell / Alienware 2GB cards. These can still be got for under $200 on eBay. The Apple card is identical in every way except for the firmware. This is the Dell / Alienware card here Grab the Apple ROM file from here: https://www.techpowerup.com/vgabios/?arc... Pay attention to...

Also wondering if there's any benefit of AMD vs NVIDEA? I see majority (if not all) of the ones here (VBIOS) are for NVidea even though the one originally with the iMac is an AMD. Not sure if there's a reason for that?