I'm using a pretty low level Displayport switch, and I think it also takes 4s to get a picture back. I guess the reason for this is actually the monitor and GP

I'm using a pretty low level Displayport switch, and I think it also takes 4s to get a picture back. I guess the reason for this is actually the monitor and GPU. They will resync to each other after figuring out the peer capabilities and probably take some time for an actual frequency sync. Therefore I don't think any kind of switch would make it better - the switch would need to be intelligent enough not to drop the display stream but be an actual GPU on its own. Plus in this case it would need to have the exact same display signal frequencies that the attached GPUs use.