You misread OPs point.  He is saying Windows can do both.  And vsync across cards. That is quite a feat. If using separate outputs, this is probably achievable on Linux with a bit of work. Also vsync with a compositor shouldn&#x27;t be impossible. However, if the processing is done on on two graphics cards and we output only on one of them then we need cooperation from the device manufacturers to provide us drivers or implementation details on how to drive their hardware muxers. Without that info, we&#x27;re dead in the water.