A Sony patent has come up in the news detailing a dual GPU console:
In a multi-GPU simulation environment, frame buffer management may be implemented by multiple GPUs rendering respective frames of video, or by rendering respective portions of each frame of video. One of the GPUs controls HDMI frame output by virtue of receiving frame information from the other GPU(s) and reading out complete frames through a physically connected HDMI output port. Or, the outputs of the GPUs can be multiplexed together.
Not sure how this could be patented though, they'd essentially be doing things that GPUs are already designed to do. Could this hint at the direction for PS5 Pro? In the patent they list the possibility of combining two GPUs on one die.