IMAC 27” A1312 Nvidia K3100M K4100M 4GB Video Card Replace 6970M with heat sink | eBay
Big Sur on iMac 27", Mid 2011, flashed 4GB NVIDIA Quadro K4100M by Nikey22, having issues with screen brightness, any ideas? Brightness control was working with Catalina Patcher, after installing Big Sur
Mid 2010 iMac 27 K4100m Gpu upgrade running Big Sur - YouTube