2017 iMac 21.5 4K A1418 iMac18,2. 2017 iMac 27 5K A1419. 2019 iMac 21.5 4K A2116 iMac19,2. 2019 iMac 27 5K A2115. Actual speeds will be lower due to PCIe Bus limitations in these computers. Update to latest computer firmware might be required. If not sure – please ask. This…