How to sync two GPU plugged into the same computer?

Hi,
I’ve got two GPUs, one is 4080 super, and the other one is 4070. They are plugged into the same computer with Window/Linux. Each GPU outputs with three DPs and one HDMI.
Now, I want to display two videos with the two GPUs, I can set the g-sync for each GPU, however, I can not control the two GPUs output videos synchronized.
How can I make the two GPUS outputs DP/HDMI with the synchronized v-sync?

Hi, I’ve been trying to answer your questions across the other threads you started…
In essence, it needs professional GPUs, Quadro Sync cards, and exactly the same screens to sync any application across multiple scrrens - attached to the same GPU, to identical GPUs in the same system, or even across multiple GPUs in multiple clustered systems…
On top of locked scanout, this will need applications to use the SyncAPI, to make them all sync to exactly the same frame, to make all GPUs wait for the busiest one, before swapping to the next frame simultaneously across all outs…
-Frank