Apple MC742ZM/A OEM/ATI Radeon HD 5770 PCIe... at MacSales.com
299-1E148-102SA Sapphire Radeon HD 5770 1GB GDDR5 128-Bit PCI Express
Amazon.com: Epic IT Service - AMD Radeon HD 5770 1GB GDDR5 Mac Edition, for Mac Pro 1,1 to 5,1 Models, macOS up to High Sierra (Attn: Legacy Model) : Electronics
This ATi Radeon HD 5770 is in mint condition... But can we game on it? - YouTube