You can have multiple cards in a system, although with the newer work units, the GPUs work together with the CPU, so you'd need to make sure you had enough bandwidth for the communications and a powerful enough CPU
Mining would happen on just the GPUs, and there wouldn't be much communication between the CPU and GPUs, hence why you would have seen mining rigs with 6 GPUs along with something like a G3220
Christopher E.R. reacted to Extingquish in GPU Folding Facts and Fiction - Configuration and Settings
