回答“What GPU's are compatible with iMac 27" 2011?”I think I'm in the same boat here. I was thinking of fitting a Radeon 6970M into a 2009 iMac. My questions are: Can I use a Windows Laptop (alienware etc) 6970M GPU card and reflow the firmware/EFI chip from an existing 6970m 1gb. What are the model numbers of the Windows LapTop cards (e,g. 1GB & 2gb versions)? What is the name of the GPU chipset used on the iMac 6970M? This is incase I were to have a new GPU chip reflowed to the existing video card i have.